The mod Ammo Alerts (2.0.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Gun_Turret_Alerts::on_nth_tick(600)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
[C]: in function 'index'
__Gun_Turret_Alerts/control.lua:77: in function 'remove_entity_from_list'
Gun_Turret_Alerts/control.lua:218: in function <Gun_Turret_Alerts/control.lua:160>

Getting the same error too after the update today; Started after about an hour of gameplay with the new version.

Should be fixed in 2.0.3