Is that high bar?
If not, it looks awfully high on your back to be low bar. Looks like you are doing the motion of low bar with a high bar placement, causing extra weight on your neck, which could contribute to the forward lean.
Depth looks fine.
Every now and then this happens to me too, the forward lean, it is best combatted with just staying tight. When you get a heavier weight on your back, you get a little sloppy and don't stay as tight until you are like "oh shit this is gonna dump over my head".
Keep the chest tight and it should fix this one issue, and I think it is a one time issue, not a problem that will repeat itself.
As for the singlet, yours looks thick (like mine). You also look big (like me), so the belt is going to feel different than when you train. Thick singlet coupled with large belly equals a lot of extra fabric to go inside the belt. Basically, the holes you normally use on your belt are either going to be that much tighter, or not able to get in at all. Something to be aware of is all.