Minecraft Version: 1.20.1

Forge Version: 47.3.0

Mod Version: 1.12

Single Player or Server: Single Player

Describe problem (what you were doing; what happened; what should have happened):
When linking up furnaces with export and import cables the game just sort of breaks. Depending on the number of furnaces it will fill up one of them with one of the exported items (for example with 4 furnaces it will fill ore but no coal into the 3rd one). The rest of them, however, do not fill up with anything at all. Other times, like when i linked only 2 furnaces, it doesn't fill anything. Seems random what will fill but so far only 1 item in the entire system will load in.

Exact same system works just fine in v1.11.3 so its clearly just and alpha thing which you're probably already working on but in case you weren't aware of it now you are :)