I'm using Bridge 2021, 22.214.171.124 on a with Mac OS Catalina 10.15.7.
Thumbnails for some photos in the same folder and same drive have been rotated while others remain in the correct orientation. The rotated images can't be returned to the correct orientation (neither the rotate buttons nor the shortcut work), although they open correctly in ACR or Photoshop. Even if I open a file in ACR, with the correct orientation, and click "Done" the thumbnail remains incorrect.
I've reset the preferences (which meant having to reorganize the hundreds of thumbnails again) but that didn't solve the problem. I didn't clear the cache with that reset ... figuring that the problem was with Bridge randomly rotating the images in the first place.