I frequently save entities with /structure. Since 1.18.30, my previously saved zombies no longer drop xp. They drop loot as normal except xp. Easy solution to this was just to re-save the structure. I’m unsure what other entities this issue effects as I’ve only saved & tested all zombie varients. Very odd bug.

I will now link a short video demonstrating this. Although the clip uses commands to convert xp into ‘Points’, it’s the same result with the machine turned off. The structure saved pre 1.18.30 is named ‘Z-Group’ while the re-saved structures in 1.18.30 are named ‘Zombie’ and ‘Husk’. Here is the unlisted youtube link:

https://youtu.be/2QMm7EEcd9I