(Also submitted in-game as 230921-002173, but wanted to post here because it's hard to explain the bug without comparison images.)
This is how you hold a shield: the hand is gripping the right-side strap:

This is how your character holds a shield on the Update 39 Live server; notice that the hand is aligned with the strap.

The same character, on the Update 40 PTS; look again at the hand and strap alignment.

The hand is no longer aligned with the strap in Update 40. I tested a handful of shield styles, and every one of them exhibits this problem, so I think it's a problem with shields in general, rather than with a specific shield style (Ancestral Breton in these images).
Nightfighters ― PC/NA and PC/EU
Dungeons and Trials:
Personal best scores:
- Dragonstar Arena: 46817 (NA)
- Maelstrom Arena: 600526 (NA)
- Blackrose Prison: 99274 (EU) (Unchained)
- Maw of Lorkhaj: 165227 (EU)
- Halls of Fabrication: 220708 (NA) (Tick-Tock Tormentor #1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #11, #12)
- Asylum Sanctorium: 114957 (NA) (Immortal Redeemer #1, #2, #3, #4, #5, #6, #7, #8, #9, #10)
- Cloudrest: 131256 (NA) (Gryphon Heart #1, #2, #3, #4, #5, #6, #7)
- Sunspire: 250866 (EU) (Godslayer #1, #2, #3, #4, #5, #6, #7)
- Kyne's Aegis: 235841 (EU) (Dawnbringer #1, #2, #3, #4, #5, #6, #7, #8)
Dungeon trifectas: