Murph
Keymaster
Post count: 918

I use fatigue to expose weakness in my programming and it is evident here.
It could be:
Weakness in upper/mid back
mobility
set up/technique

Try adding these in a few times a week:

and

and

As you were fatigued here it is more pronounced.

The mobility work may help, especially if you work at a desk.

Does this issue happen on regular deadlifts?