I have a specific model that has a total of 3803 layers however when printing it is printing 3457 layers which is also displayed in the print status. At around 3457 layer the print head runs into the layer and knocks the model right off the supports printing possibly the remaining layers into a spaghetti mess. The whole thing is quite strange. I have tried a fix however no issues are discovered. This is a paid model and quite a popular one. I have never paid attention to the number of layers in the print status so I am wondering is this normal for the number to be different like this? Seems like it could be where the issues are in that it prints to this layer before running into the model.
Which supports are you using ?
Currently using tree slim on this model. It is made up of 12 different parts and this is the last part.
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Hybrid Tree is all I use
I’ve found the support branch angle for regular and slim tree seems to be a bit optimistic for single wall supports
But the hybrid tree supports have worked flawlessly for me
I know 100% regular and slim can be dialed in and they will work beautifully but I don’t have the time currently to play around with them
So in other words I’m lazy and the hybrid tree supports are the lazy mans supports 
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Also tried tree grid and it was also very strange the outcome. See this link. https://www.reddit.com/r/BambuLab/comments/10uextk/layer_shift_on_specific_model_part_at_specific/
So when using tree slim it runs into the model tipping it over and with tree grid it performs a layer shift. Both these occur at the same layer which from what I can tell is at 3457 when there is still many layers left.
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I really don’t think this is a support issue. The model is very stable, what seems to be happening is the slicer is miscalculating the layers or something and the print head runs right into the print at 3457. Hell I don’t know, never seen anything like this. I got a feeling tree hybrid it may still be standing however the massive layer shift will have occurred similar to tree grid. I will give it a go however starting to speculate this is a bug with the slicer and this model.
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Would this occur if your extruder was not calibrated? Say it was over extruding would it result in a failure after so many layers? I did have a similar problem that occurred twice in a row at the same layer when the printed part was under height (different printer).
I will give it a full calibration and try the print again tonight. Still, the fact that the print status is showing only 3457 total layers and that is where the issue occurs seems like the issue is baked in before it gets to the printer.
There are many posts showing inaccurate layer counts. I am skeptical that this is in any way related to the head crashing issue. Keep in mind that Gcode doesn’t know from layers other than comments inserted by the slicer - it’s all about XYZ motion.
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@holmes4 - Thank you for that feedback, I did not realize others have also seen these incorrect layer heights. Got a few hours left on the latest attempt. With the current print I created a new project, verified Variable layer height is off, it always was, ran a fix on the model however don’t think anything was fixed as I have tried other programs to fix the model and none of them find anything to fix, also ran a full calibration on the printer before starting the print. As a side note I am not having issues with any other models or prints and this is the last of roughly 12 parts in this model and the other 11 were fine.
here is some pics of the current progress and slice.
The 3rd pic is illustrating where the print status ends from layer count, 1st pic is the full model including all layers. The 3rd pic is typically where the prints fail and gets knocked over, I got a pile of these failed prints all up to this point.
And here is a timelapse of yesterday’s failure. video 2023 02 06 17 20 21 - YouTube
Notice how abrupt the failure is, it simply is knocked over without signs that the model was loosing stability. The crash happens at roughly 2:15
And here is the one time it did actually finished without tipping over. Notice the layer shift is occurring at the same point the model tips over when using tree slim supports. I believe the supports used in this version was Tree Grid however with the layer shift occurring in roughly the same spot instead of tipping over it’s still not a usable print. video 2023 02 04 14 43 11 - YouTube
Did you try increasing the base of the supports (the area that’s touching the bed)? There might not be enough contact area to hold up that much weight.
In this version of the print I used Tree Grid rather than slim and it was still standing after the print. The print was very stable and showed no signs of wobbling and required me to scrape off. So instead of tipping over a layer shift occurred in roughly the same spot it normally tips over. The shift occurs around 1:50 video 2023 02 04 14 43 11 - YouTube
So I am not sure adding more support at the base is going to help as in this one it was stable during the whole print.