No.
This is a slicer artifact. Plain and simple. All slicers do this. It has to do with the method it uses to optimize the outer wall path intersects the actual model.
Reducing layer height forces higher resolution and less errors on XZ and YZ holes.
This is a slicer artifact - but of Bambu Studio. When I slice on Cura it does not oval the holes.
Additionally - the Voron manual states .20 layer height, .40 layer width.
I just finished printing the heat set insert test part at .10 layer height and the holes are still oval.
Iām doing some more testing and will report back.
Printed the same model on my Voron using Cura 5.3 beta - .20 layer height, .40 line width, 40% infil, 80 mms
Side by side comparison of multiple prints from Bambu Studio (OrcaSlicer) with various settings but same settings as above.
I agree your problem is an artifact problem, but the OPās may turn out better if he reduces the layer height since 0.4mm is pretty high. As for your problem, what speed are you printing at? Iāve found that Iāve generally had to slow things down for non-bambu filament.
I hope his layer height was a typo - the Voron docs say .20 mm 
I have slowed mine down to 80mm/s for all lines. I am in the middle of one more test right now - I sliced the model in Orca but for the Voron. So far, the print looks like the holes on the vertical surface are correct - so that points back to the X1CC or a particular slicer setting that is for the X1CC but not available for the Voron - Iāll have a picture shortly
@BambuLab Any thoughts on the information included above?
To recap - I have tried:
The only thing that worked: printing on my Voron instead of my X1CC
I think this might simply be an issue of traveling and accelerating too fast for the smaller perimeters
And your wall order can definitely affect not only visual aspects of a print but most definitely dimensional accuracy if your wall order is outer walls first
Just some simple ideas for a complex issue
We get so used to printing fast with good quality with all types of materials that sometimes itās difficult to figure out whether weāre going too fast or too slow for a particular model printed with a particular type of material
Iām playing with vase mode as Iām replying here and although this is strictly used for pretty demonstration prints it is actually a helpful tool for determining certain artifacts that can be tuned out when printing in regular mode with more than 1 wall on a larger scale
Other than the 1 wall and constant motion while in vase mode absolutely every other setting Iāve found has the same relevance and affect between the 2 modes
That may seem rudimentary to you or others but these are a couple of those things that I keep in mind whenever a print doesnāt come out dimensionally correct or as in vase mode will show has ringing, layer adhesion issues, over or under extrusion and temperature related issues like stringing or ugly outer walls in one or all horizontal walls
My biggest bane right now is dialing in the seams but thatās a discussion for another day, I hate highly visible seams lol
Those layers on the OPās photos look like theyāre .28, not .20, so yeah youāll get bridges instead of a rounded top of the hole. Why are you surprised?
Just for giggles I printed a Voron part with generic no-name ABS, in white so the holes would stand out better on the photo.
ā0.20mm Standardā settings on Bambu Studio, 0.4 nozzle, all stock slicer profile settings, no speed changes, no profile changes except for 4 walls instead of 2 and 40% infill as per the Voron specs, all stock generic ABS profile, no tinkering with belts or anything else. Flow calibration enabled.
Fresh of the build plate those holes look pretty round to me!
So Iām thinking, itās not the machine, itās not the slicer, it must be you. Sorry! 
Have you measured the X, Y and Z dimensions of the part? Thatās the only thing that matters. For having built 3 Vorons prior to buying a X1C, I can tell you that the roundness of the screw and heat insert holes play zero role.
If the part dimensions are correct but the holes are not as round as you like, do what everyone else does, use a drill.
Youāre missing a couple of crucial points:
If you donāt mind, please print the heatset test part that I referenced in my post:
Voron-2/STLs/Test_Prints at Voron2.4 Ā· VoronDesign/Voron-2 Ā· GitHub - Heatset_Practice.stl
If yours prints without distortion then I might consider itās me and not the printer / slicer
Additionally, if you can supply your .3mf file that would give me a good idea of your settings compared to mine.
Thanks
Oval holes can apeare if the tension of the ābelts?ā of your Carbon X1 is not correct. You have two ābeltsā in your 3D printer. Both of them need to have the almost the same tension, else you wont be able to print round holes.
There are many tools you can use to messure the tension of your printer. I have a video on youtube from a german guy who expalins what happens, if the tension of your printer is not setup correctly: you start to print āOvalā holes.
Here is the video. Sorry its in german, but if you scroll to this time line, you see what he touches and how he mesaures the tension:
Watch from: 11:34 Minutes, he explains how to correct the tension of the two belts of the printer:
This is the tool he uses to meassure the tension frequencie to make it equal on both āRiemenā (belts):
I hope that helped.
Thank you - Iāll check the tension. I will note that I have performed the Bambu approved retensioning procedure several times - maybe itās just not working properly.
LOL - I just saw the price of the belt tension meter - if I have to spend another $500 to get my $1,400 printer to print round circles ā¦ I dunno man - thatās just funny.
Iāve provided all the detailed settings in my previous post.
Thereās a chance my new results will frustrate you even more.
Iāve printed the test piece youāve requested with those settings: perfect holes on the first try.
The heat insert goes in very snugly without squirting out plastic: perfect size.
As you can read on the caliper weāre very close to the partās intended dimensions : perfect in my book too.
So yeah, I do get that different people will get different results and that ādozens complain on several forumsā, but you canāt expect everyone to be very good at this. But thatās the thing: this printer and its default profiles were designed to ājust workā for first time users, and I can see they do.
Average or experienced users will look at the settings and think āwell thatās not rightā and change them to what they were used to on their other printers/filaments, then of course it messes up the print, but instead of questioning what they just did they question the printer, the belts, the slicer, Bambulab and everybody else under the sun. The same as on every other forum for every other printer ever made.
Iāve had many printers since 2014 and my conclusion is that this printer is the best Iāve ever had because it prints perfectly WITHOUT me having to spend countless hours fine tuning it.
But who knows, perhaps I was just lucky!
Weāll see how it holds up against time and wear, but so far itās the best affordable non-industrial FDM printer out there that you donāt have to build yourself.
Your post does not frustrate me at all and I appreciate you taking the time to post.
Iāve been printing professionally since 2019 and selling printed models on Etsy so Iām experienced as well. In addition to that, Iāve had many printers and built a Voron from parts.
Looking at your top photo, the outer portion of the holes appear oval - with more dimensional accuracy INSIDE the hole. I also measured
the inside diameter of my prints and they are correct - but as the hole gets closer and closer to the outer wall - the horizontal dimension gets larger than the vertical (itās an oval shaped cone).
Iām going to print an actual Voron part instead of the test part to see how that looks - maybe itās just the test part that is looking so oval-ish.
Top model (beige) printed on my Voron - bottom model (black) printed on my X1CC - same model, same slicer / settings.
Again - I appreciate your input and expertise.
UPDATE:
Wow - itās even worse when printing larger holes. Here is a Voron tensioner part. Itās really squishing the holes. The model has a z height of 18mm and the printed part ends up at 17.98mm - so itās not squishing / skewing the part in the Z axis - itās just the holes - and youāll note the hex nut hole is also squished down.
Iām at a loss here - Iām going to try formatting the SD card and printing again
Mark
One other thing I am investigating - this morning I did a rod cleaning and belt retension maintenance cycle. I noticed that the print head had what felt like some binding when sliding along the Y axis - it was subtle so it may have been me introducing a slight amount of X travel as well. Iām going to lubricate the idlerās later today to see if that makes any difference.
I donāt think this is the issue as I can move the part anywhere on the bed and I still get what I am now calling a āoval coneā effect (the hole is a circle INSIDE the part but flares out to an oval cone as it approaches the perimeters.
I hope you are kidding. Itās called perspective. The second photo which you are ignoring shows the exact same holes seen from the top.
Iām not kidding at all - the color of the filament and the lighting makes it look not as prominent in your second photo.
Iām showing real proof there is a problem here - Iām genuinely happy your printer / environment is giving you prints that are satisfactory - but mine is not.
I canāt help you.
Try printing with Tree supports.
Hereās another out of the box idea: since youāre (apparently) printing parts for a Voron, use them as-is for now. To build a Voron the only thing that really matters is accurate external dimensions. (Iāve printed the parts for my first Voron using an old MakerGear M2 and it turned out good enough)
Then use the Voron to re-print the parts you didnāt like.
When you got the Voron all fine tuned to your liking, sell the Bambu.
