Playing with both Wither Storm Mod and Realistic Block Physics mods causes the latter's physics engine to crash.

The thing is it doesn't crash the actual game, it just makes the RBP mod stop working properly. It's not hard to reproduce, though. Just install both mods, join a world, and see physics not working and some lag.

I need a crash report to figure out the issue

Interesting. Could you try turning off "Tick In Containers" under the "Formidibomb" config?

I just tried it, block physics still don't work. This time it took a bit longer to reproduce though.

Will have to investigate further then

Just was testing and noticed the mod was acting normal, and I'm unable to reproduce this issue. Did you have any other mods installed when you encountered this issue?

Sorry, it wasn't a crash. It was actually just extreme lag

Ah, got you