The portal you activate with eternal shards appears to be broken. It may be a conflict with another mod, but I don't have any that change portals or dimensions significantly.

Do the portals work for anyone else?

I am not able to replicate this. Show the crash report please

Could you provide a list of the mods you are using and maybe a screenshot showing the problem?

Pre-entering portal.

I have reloaded the single player world after it crashed and now it simply teleports me to the opposite side of the same portal. Mod list incoming.

modlist.txt
Quite a few mods I'm afraid!

I think pre-crash it was teleporting me back into the portal over and over causing a load loop.

Ok, it seems the load loops occur when you open the world to LAN. It simply creates an endless dark screen as if you are entering a dimension eternally.

i have similar issues, most of the time it boots me back to the end side, but if i jump into the portal then it will sometimes go to the overworld

New version out, if the issue persists please, open another issue. I'll close this for now

All right, i think i fixed the issues related to the End Portal, in the next version it should work as intended. When next version i released give feedback on that please, so i can eventually declare this issue solved and close it