Unity messed up weight painting from FBX file exported from Blender Here, this is the model I made, "RightMainBayBone" is rotated and it rotates connected meshes:




In Blender, it works fine. But when I imported in Unity and rotate the bone, it also rotate other meshes:




Rotating Left Bone doesn't make this problem.

I exported as FBX with apply transform option.

I think this is Unity's problem but I'm not sure, because there might be something I missed.

Any advice will very appreciate it.

p.s. There's no parented bone.
Unity normalizes weight per vertex so you can't have vertices with zero weight. So the armature needs to have a root bone that you use to paint the weight of parts that don't move.