Exiting the end portal first time removes player attribute modifiers

How to Reproduce

1. Add a attribute modifier

   /attribute @s minecraft:generic.max_health modifier add a 1 add_value

2. Exit the end (make sure the end poem appears)

Expected Behaviour

The max health is 21 (the modifier wasn't removed)

Observed Behaviour

The max health is 20 (the modifier was removed)