I'm not sure what causes this crash, as it happened when I installed it. And the crash report isn't obvious to me what happened. It doesn't seem to be a conflict.

Crash report:

https://pastebin.com/2FzGeEFf

Affected versions ("latest" is NOT a version):

• Minecraft: 1.12.2
• Forge: 14.23.5.2838
• AbyssalCraft Integration: AbyssalCraft+Integration-1.12.2-1.9.0
• AbyssalCraft: AbyssalCraft-1.12.2-1.9.10

Latest log file for when the issue was present:

latest.log
Linking file because its too large for pastebin

Got it.

Update Bewitchment. AbyssalCraft Integration 1.9.0 supports Bewitchment 0.0.20, which included a big rewrite on their end, which makes the integration incompatible with earlier versions of that mod.