The Mod Spidertron Engineer (1.2.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event SpidertronEngineer::on_research_finished(ID 18)
The mod Spidertron Engineer (1.2.1) caused a non-recoverable error.

Error while running event
SpidertronEngineer::on_player_driving_changed_state(ID26)
SpidertronEngineer/control.lua:211:attempt to index field
'player_last_driving_change_tick'(a nil value)
stack traceback
SpidertronEngineer/control.lua:208>
(C): in function 'set_driver'
SpidertronEngineer/control.lua:138:in function
'ensure_player_is_in_correct_spidertron'

kinda repeates from here but the control.lua numbers referenced were also 163, 354, and 351

Error was triggered by completing the technology Military 2

I think that that is because I messed up the update logic in 1.2 so that global field never got set. Fixed in 1.3.

I figured it was something like that. Thanks again.