154.107 Error MainLoop.cpp:1510: Exception at tick 13148400: The mod Signal Display (1.5.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event signal-display::on_nth_tick(30)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
[C]: in function 'index'
__signal-display/scripts/events.lua:33: in function <signal-display/scripts/events.lua:9>

Thanks for the report.
Can you give any further context?

Other mods active, what you were doing?
Any surfaces recently created, deleted?

Crash likely due to access field in display that is considered invalid.
Additional safeguards added in v1.5.2 that seem to fix.