Updating to 1.19 was fine, but on my 3rd playsession in the update most my mobs disappeared.

My iron farm/villager trading hall (located approximately -525, 90, -525) was empty 
My stables and cow farm (located approximately -900, 64, -200) were all empty too.
My nametagged dog was also gone from this location.

I regularly travel between these places via the nether.

Some mobs did survive but these were mostly at other locations. Idk how to replicate the issue but I will restore my world from a backup and append this post if it occurs again