Sometimes the bevel acts a little weird for me for some reason. Bevel modifier settings.
You may have double vertices or flipped normals. Try recalculation your normals, select all and the Shift + N and select everything and M to merge by distance.
yep. Could that be why? When I recalculated those outside, most of the bevel got fixed, tysm!
Yes, that's your problem; inconsistent Normals! Like Omar already said:
In Edit Mode, Select everything (with A) and SHIFT+N. That should take care of it.
Won't do any harm to M > Merge > BY Distance as well.
