Originally Posted by
fietsbob
Under torqued on installation, I suspect. not tightened enough when installed.
Perhaps, but the OP reports that not only did the NDS side shift out of the frame's BB shell, the whole spindle moved to the left too!
Hmm, maybe this is one of those "cartridge" BBs that use two off the shelf cartridge bearings pressed onto a spindle with a spacer tube between them. Perhaps the pressed together parts on the drive side slipped/walked.