The *.work files contain the current/temporary state of the project (in this case pattern bank 16). For each of the *.work files there exists also a *.strd file which contains corresponding “save state”.
Since I wasn’t in this situation before, I’m not sure how the OT behaves by itself, but manual project recovery may also be possible by replacing the invalid file with its other variant (*.work or *.strd depending which one gots corrupted). Of course, this doesn’t guarantee a full recovery when the current state and the save state already differs.
About why this may have happened:
My first guess wouldn’t be a bad card/bad sectors. It’s much more likely that you turned the OT off before it had completely finished writing the current state files to the CF card.
Before turning the OT off always watch the card status led careful for inactivity.