The mod Combat Robot Overhaul (2.1.25) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event CombatRobotsOverhaul::on_pre_player_mined_item (ID 14)
CombatRobotsOverhaul/control.lua:154: attempt to index a nil value
stack traceback:
CombatRobotsOverhaul/control.lua:154: in function <CombatRobotsOverhaul/control.lua:149>

This happened when I tried to mine a red belt ghost (created as a replacement for the belt ghost being destroyed).

Thanks for the information. The event filter didn't trigger correctly. Should be fixed as of 2.1.26.