Short description:
When mining an entangled underground belt (eb-), the game returns the base underground belt instead of the entangled version. This breaks consistency (placing eb- but receiving normal belt back).
Fix (minimal change):
File: prototypes/entities.lua
Replace:
eb_entity.minable.result = underground_belt.name
With:
eb_entity.minable.result = "eb-" .. underground_belt.name
This ensures the mined entity returns the correct entangled item.
Additional note:
The above fix was generated with the help of GPT AI. Nothing personal :p