What’s causing these “gaps” or holes in my ironing? The pink is Bambu Basic PLA. You can see it doesn’t happen everywhere, just in spots. I also ran a few test prints before printing the whole thing and didn’t have the issue. Any suggestions?
Man, you need to turn the steam on and you should try to spray some starch onto your shirts before you iron them !
Oh wait, we are talking about printing issues you said? My bad 
The ironing works best on surfaces free of interruptions, gaps or impossible to reach areas for these infill lines.
A lot has to be right in order to get the best possible result.
It all starts with a good calibration of temp and flow ratio followed by the k-factor to make this part complete.
Printing top surfaces is often tricky, even if the filament calibration is spot on.
Not always is going at a snail’s pace giving the best result, especially with silk and matte filaments.
Depending on the model’s needs and filament properties one might have to adjust the flow ratio for top surfaces to avoid a build up along the walls within tight spots and such.
You can abuse this top surface flow ratio adjustment by creating a dedicated ironing profile.
Lower the top surface flow ratio to the point where you have no build up in the usual problem spots even if it means ending with slight gaps between the lines here and there - no build up anywhere is the way to go.
Now use the flow settings in the ironing feature to extrude just enough plastic to properly fill these gaps while producing a really smooth surface.
Try to find a balance between your top layer infill line width and your ironing spacing/line width.
E.g.: Have the ironing lines one third of your top infill line width while also going in the same direction.
On the other hand, printing this test logo upside down on a smooth plate might give even better results - just saying…
Strongly suggest using this test print for ironing calibration
Ironing is finicky. Even with this test, the small blocks aren’t truly representative because of the small surface area, and in your case, the amount of times it has to retract and dodge the text area. Ironing is one of the most precise things you can ask your printer and extruder to do. Bulldozer blades are shaped quite different from a nozzle, and you’re asking it to do that
I like this test because I can compare the poor result, and get a starting point for what direction i need to start moving the settings. (Ex: as this filament gets faster, it gets more ragged… or vice versa. etc)
Good luck!
I would start with increasing the flow to 20%
Would you?
And based on what exact factors?
Just by my own experience, default flow of 10% is too low