Minecraft Version: 1.20.1
Forge: 47.3.0
Mods:
ATM9 TTS 1.1.2 modpack from CurseForge, or also with fewer mods:

To reproduce crash:
- Place a Hyperbox and enter it
- Place a Flux Point
- Create a network and set the Flux Point to it (no power needed)
- Place an ME Controller (or Energy Acceptor) beside the flux point
- Exit Hyperbox
- Break the Hyperbox
Notes:
- Powering the ME system directly through an energy cube (e.g., basic) won't crash
- Powering the ME system through a universal cable (from Mekanism, e.g., basic) will also crash, regardless of power source (creative cell, even w/o Flux Point)
Related to #18