A Vex in a minecart or a boat will be sitting lower than it should, with part of it's texture going underneath and only it's head visible from above. 

This a problem now because of it's new look that makes it's model smaller and lower in it's hitbox.

Attachments informations :

Second attachment : There is an Allay in the minecart on the right.

Third attachment : There is also an Allay in the boat.

Two last attachments : Same situation but in 1.19.2 with the Vex's old look.