The Bug
When unlocking an advancement and a recipe at the same time, the resulting toasts seemingly don't slide in and out in a synchronized manner.
Reproduce
picking up an item that unlocks both an advancement and a recipe, such as an iron ingot for the Acquire Hardware advancement.
Observed Result
The two toast were out of sync
Expected Result
The two toast would be in sync
Something i noticed when trying this a few times, is that the delay between both toasts varies, and i even got some attempts where it did sync correctly, so it might depend of server tps.