Getting this as well. Strangely enough, I can only get it to occur when I drag another part (the attachment’s parent in my case), ctrl-z, then attempt to drag the attachment. Weird.
This also happens to me as well (specifically @tacovalk’s response). It started happening around the time when draggers had the origin set to the pivot point rather than the center of the model.
Another thing to add is that pivot origins are also modified when attachments are moved. PivotTo and other functions that rely on this are no longer accurate when this happens (I haven’t tested this very much, PivotTo might still work fine, but it’s something to look into).
Simple fix for now: if you’re trying to move the attachment and this happens, rotate the attachment first, then try moving it. Fixed it for me. Vice versa for rotating: move the attachment, then try rotating it.