There is a rendering issue with the Inverted Skyblock from OpenBlocks, an issue that is causing all players around a placed Inverted Skyblock to crash out constantly. This issue does not crash the SERVER, but it will lock all players immediately around the placed block to get locked into a crash loop. I strongly recommend that everyone using ALL versions of my pack to go into the Openblocks.cfg config file, find the Blocks section, and change “Sky=true” to “Sky=false” . This will disable the Sky block and Inverted Sky block completely and remove all existing troublesome blocks from the game world.
This is apparently a rendering bug in OpenBlocks, and I’m planning on an update to that mod in v1.08 of the modpack (which is still some weeks down the road).
Hope this helps!