Sometimes when I use Ctrl+Z to undo I get an error and im thrown out of my current game, though not out of Factorio.

The mod Ore-ganizer (0.9.9) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event ore-ganizer::on_undo_applied (ID 188)
ore-ganizer/control.lua:1086: attempt to index field 'target' (a nil value)
stack traceback:
ore-ganizer/control.lua:1086: in function <ore-ganizer/control.lua:1080

Thank you for reporting the issue, investigating now.

Version 0.9.11 has been uploaded, it should resolve this issue.

I am curious, what Undo action does not have a target entity? Do you recall what you were attempting to Undo?

The first time it happened on the custom mining drills from this mod so I thought specifically they were the problem.
But then it also happened when I did Undo on some assemblers for iron gears.
Note that I am using a mod called Quantum Fabricator that sometimes has strange interactions with other mods.

Ah, interesting. I will do some testing with the mod.