Same for me
 

Yeah, I'm experiencing the same thing. However, my issue is with bank slot 12 only. For me that is the only one which continues to reset itself to the default location and size.

Same here. I found that by going in to UISettingsSpy and deleting 4 inventory windows (ones with oddball numbering in their names that didn't fit in with the others) I eliminated the problem and got my bank bag windows saving correctly without messing anything else up (that I can tell). I'm not sure I recommend that for the ordinary person, though. Although... what are the consequences of just deleting all inventory bag clone windows and entering the game? Would that mess things up, or would the windows just be re-cloned and I'd have to reposition and resize them again? I may try that just to see.

Yes, you can just delete them all if you want, that's no problem. The "oddball" ones are those I referred to above, that was the bank window hack. I'll remove them one of these days.