discovered by @deli73
Fabrication version 1.2.3_01

Expected:
Upon entering the return portal from the end and watching/skipping the credits, you should return to your spawnpoint with all your experience and items.

Actual behavior:
Upon entering the return portal from the end and watching/skipping the credits, you return to your spawnpoint with all your items but none of your experience.

Possible cause:
The end return portal calls respawn methods to return you to your spawn point. The lose-xp-on-death feature may not be properly detecting that a respawn is due to end return portal usage and resetting player XP anyway.