Submitted to me (FTB Beyond pack dev): https://forum.feed-the-beast.com/threads/iron-backpacks-achievements-crash.220654/

Issue Description:

When panning to the upper left corner of the Iron Backpacks achievements screen, the game crashes.

What happens:

Game Crash: http://paste.feed-the-beast.com/view/9a4ac3f7

Affected Versions (Do not use "latest"):

• IronBackpacks: 2.2.23
• Minecraft: 1.10.2
• Forge: 2254
• Other Conflicting Mods (may be irrelevant to your issue):

Thanks for the bug report! I'm swamped today, but I'll try and fix it tomorrow.

Looks like it is a Forge bug and happens with all mods.