Robot Build:

The mod FFF 402 radars (1.0.5) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event fff-402-radars::on_robot_built_entity (ID 14)
__fff-402-radars__/control.lua:18: the surface's radar circuit relay got invalidated, what happened?
stack traceback:
[C]: in function 'error'
__fff-402-radars__/control.lua:18: in function <__fff-402-radars__/control.lua:10>

Repair Turret Build:

The mod Repair Turret (1.0.3) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Repair_Turret::on_tick (ID 0)
The mod FFF 402 radars (1.0.5) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event fff-402-radars::script_raised_revive (ID 81)
__fff-402-radars__/control.lua:18: the surface's radar circuit relay got invalidated, what happened?
stack traceback:
[C]: in function 'error'
__fff-402-radars__/control.lua:18: in function <__fff-402-radars__/control.lua:10>
stack traceback:
[C]: in function 'revive'
__Repair_Turret__/script/repair_turret.lua:615: in function 'build_entity'
__Repair_Turret__/script/repair_turret.lua:779: in function 'update_turret'
__Repair_Turret__/script/repair_turret.lua:888: in function 'check_turret_update'
__Repair_Turret__/script/repair_turret.lua:991: in function 'handler'
__core__/lualib/event_handler.lua:47: in function <__core__/lualib/event_handler.lua:45>

this error means something broke before a robot or repair turret tried to place it, did you delete a chunk or something around the work center or did something destructive there? (possibly launching a spaceship)

Nope, this is happening on a moon mining outpost, several hundred tiles away from any rockets or spaceships (I haven't done much with spaceships on that surface), I was trying to put a radar on a remote stone mining patch

did you ever press trim on that surface or do something tight at the center of the world?

yes, several trims over time. is that the issue here?

yeah this mod adds a "main" entity all the radars draw a hidden wire to at {0, 0} and the mod has a sanity check that if it gets into an invalid state (aka somehow the entity not existing anymore) that it gives this error on purpose