I've managed to recreate the bug, again crashed before I could save it. I'm trying to modify some late game science builds with beacon columns to make them more early game friendly, and upgradable to the fully beaconed setups. This means I'm dealing with a lot of tight underground belts in the blue ...

factorio.log: https://pastebin.com/nJ0Duzqk

The setup, place an underground belt and on the other side place a ghost underground of the matching type.

To cause a crash quick replace the actual underground with a different tier.

I've tested this with fast -> normal quick replace.

factorio.log: https://pastebin.com/Ag0cxC4Q I was setting up some blueprints, and trying to split it into 2 logical parts and putting them into a book. I had edited them a few times and there was no issue, one time at the moment I opened up the blueprint's gui (from inside the book) the game hard cr...