Version Info

• Minecraft, 1.20.4, NeoForge 20.4.237
• Entangled, 1.3.18

Steps to Reproduce
Bound Entangled#1 to Entangled#2
Bound Entangled#2 to Entagled#1
Trying to break

Crash report (~/logs/latest.log)
latest.txt (Can't upload with a .log)

Notes
I was unable to reproduce this bug on the Fabric (0.15.11)

This has been fixed now in Entangled version 1.3.19 for NeoForge 1.20.4 - 1.21.1.
Thank you for reporting the issue!