"Vertically bowed" brick foundation wall

I realize the pictures aren’t the greatest and hard to see, but hey, it was under a deck and this is the best I could do. Anyway, the wall was bowed inward at the middle. Couldn’t access area from interior. So my question is, what causes “vertical bowing” of a foundation wall?

Usually, improper water drainage at the foundation causing excessive weight against the foundation.

Hydrostatic pressure of some sort, probably. Does it have a high water table, a lot of rain…heavy soils, etc.?

It looks like a roofing nail in the joist hanger…