Minecraft: 1.16.5
Fabric:    0.11.6
FabricAPI: 0.37
Immersive: 0.90

https://mclo.gs/0VGCiXj What happens WITH immersive portals,
https://mclo.gs/FQTAyWu What happens WITHOUT immersive portals

# Actions Taken on World Gen
1. Create Superflat world
2. Put Datapack in world/datapacks
3. /datapack list
4. /datapack enable (the datapack)
5. /difficulty peaceful
6. /function lj:rez/batons/4
7. Attempt to use baton to fly with 4th Gen Light Jet

Tron Light Cycles Datapack
Tron Light Cycles ResourcePack

Without Immersive portals, the Datapack allows me to spawn in a Light Jet and fly around,

With Immersive portals the jet does not even attempt to load, it will play load sound, and entities will start to spawn, but then it just dies

Does this issue occur in the latest 1.17.1 version?

Unknown, As I do not have access to the 1.17 datapack for the Tron Cycles.

Maybe related with some edge case entity tracking mechanics that IP changed

Potentially, but its odd that it doesnt break Light Cycles as well as Jets. It only breaks jets and lc:the_grid dimension.

Close because outdated.