I encountered this crash while anchoring a spaceship which had a spidertron patrol point on it, and a spidertron idling at that point.

The mod Spidertron Patrols (2.6.4) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event SpidertronPatrols::on_nth_tick(5)
__SpidertronPatrols__/scripts/spidertron-control.lua:201: attempt to index field '?' (a nil value)
stack traceback:
    __SpidertronPatrols__/scripts/spidertron-control.lua:201: in function <__SpidertronPatrols__/scripts/spidertron-control.lua:134>

The log gives no additional information.

Seems like it only happens when the waypoint is set to wait for a circuit signal.

Also, strangely, if you launch a ship with a spider idling at a waypoint, anchor it, and THEN change the waypoint to circuit, it usually causes a crash.

Hopefully fixed in the next update, feel free to try it from GitHub in the meantime.