In a singleplayer world in my modpack, I end up getting some crashes. I don't know what would cause the incompatibility in this case. I don't have C2ME installed, and the Immersive portals errors happened before the crash and not during it. The client stays open but it says "Connection Lost" with "Internal Exception: java.util.ConcurrentModificationException"

null[221611] [mainINFO] Loading Min.txt

It is over 300 mods, however it is stable outside of when I added this mod, but it seems to only happen when shooting Sometimes. Help is appreciated

Upon some further testing:

• Opening world to LAN causes the crash to become less frequent
• It is a softcrash, meaning every position and inventory saves before closing the world
• Redirects to Serverlist even when it was a singleplayer crash
• most commonly happens when mob is shot in the torso from eye level, or in the head from way above

Please test with latest.