https://mclo.gs/X6aRYIN
Quite odd, but I figured to report it just in case it's useful.
Indeed dimension 6 does not exists in the modpack, and for some reason TA is mentioned there. Only occurs when entering that one particular testing singleplayer world.

That's extremely strange - the only way it would try to load that is if the Entity said it was in dimension 6. It's technically possible since it only checks the integer dimension field which someone can just set to whatever they want, but why?

Likely caused by some other mod's activity? Feel free to close this 🙂