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About half the time recently when printing with PLA, I see that holes or loops have a line of filament running approximately through the middle which seems to be one of the inner perimeters having detached and contracted, but is still attached on both sides. Is it a temperature thing, an extrusion thing? I can't find a pattern. Bed adhesion is great. Bambu H2C, mostly printing with Bambu Basic PLA.
Those sections of extrusion are being pulled away from the print as the nozzle moves, because for whatever reason they are not adhering to the rest of the print properly.
Increase print temperature, reduce print speed, or reduce travel move speeds.
Also a sanity check, look at your slicer's output preview and ensure nothing about that model is causing it to freak out and attempt to print in midair...
I'd considered raising the temperature a little to get the perimeter to stick better to its neighbor, but I wasn't sure if hotter printing would worsen the thermal contraction, which is what I was originally suspecting was happening. Nothing ever pulls off from an outer perimeter, it's only inner perimeters of empty loops or holes.
Isn't that obvious? Try making a circle of a certain size on a flat, empty table, by dragging a string. The circle will become smaller, than the target size because of the drag.
Now drag the string around a gluestick, it can't be smaller than the gluestick's circle because the gluestick is in the way.
Your nozzle won't travel anywhere outside of your model's outer perimeter because it has no reason to (unless your g-code is super borked, see my comment about your slicer above) but it will be dancing around within the space between the outer perimeter and center of your model many hundreds of times. Any extrusions pulled off on the outer perimeter would stay somewhere within the model.