Shield in offhand breaks upon weapon/tool breaking.

I've seen another report for this, but I've had about 5 shields break now on Java 1.21
At first I thought I was somehow throwing them without noticing, but I finally caught it on video (attached below).

Basically as soon as my axe broke so did the shield, but I had just crafted it and didn't use it to block.

Hope you can figure this out!