I deal with shoddy work all of the time. Bathrooms are ripe with shoddy work but you still don’t just see holes right through walls. It’s not how the materials tend to fail.
You were previously dismissive of the idea that the wall is dangerous and compromised, but that is now very much what you are postulating. The substrate is the wall. If there is movement so extreme as to cause a hole it isn’t going to cause a single small hole. These aren’t mosaic tiles that can shift in the mortar bed, they’re large tiles that would have wide cracks. Water damage would extend far if it is extensive enough to cause a hole in a vertical surface. That’s really bad and potentially quite dangerous if it’s happening in a stud wall, even more so if it is a block wall. Yes, the hole in the wall could have been pre-existing from something else like the prior fixture, but then we’re still heading back to the magic spot that whatever happened (wall movement, impact, whatever) just happened to that one tile that was aligned just right with the existing hole.