Describe the bug
When you generate (or pregenerate with /forge gen command) chunks the server crashes

Does this bug cause a crash?
yes: https://pastebin.com/fvA92Vg0

Side
Server side (i think)

To Reproduce
Steps to reproduce the behavior:

1. Host GregTech Experimental on a server
2. get inside that server as a client
3. generate some chunks (/forge gen ~ ~ ~ 1000 should be enough)

Expected behavior
it simply crashes, the client seems unaffected

Screenshots
no possible

Additional context
i think this may be fault of GregTech only, i experimented a similar issue with Surival Inc. with a Client-Only constructor, maybe it is happening the same here, but maybe it will be related to Railcraft and Recurrent Complex according to VanillaFix

i would like to add that this issue seems to happen too in SinglePlayer, it is the first time i see it
https://pastebin.com/pTLkFqF1