I was testing the solar laser in Editor extensions world, with Exotic industries modpack +QOL, when this error occurred, not crash, contrary to my title.

The mod Cheese's Concentrated Solar (0.3.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event ch-concentrated-solar::on_nth_tick(120)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
[C]: in function 'index'
__ch-concentrated-solar/control/beams.lua:19: in function 'generateBeam'
ch-concentrated-solar/control/nthtick.lua:42: in function <ch-concentrated-solar/control/nthtick.lua:7>

Thanks for the report, these errors are just getting weirder.
Could you confirm if you were using editor mode/paused time/any other strange circumstances when the crash occurred?

Using editor mode, I was spawning/despawning small biters in range of the solar laser. The error might've occurred a second after I manually removed the last biter.