Factorio Forums

In editor mode
Place an entity(assembler) or do some other action.
Paste a blueprint, blueprint gets instantly created.
Press undo, it removes the assembler instead of the pasted blueprint

Thanks for the report. The map editor and the undo/redo do not mix well/if at all.

If you plan on using them in the editor you'll need to disable the instant-deconstruction/instant-blueprinting.

There's no perfect solution that I can think of simply those editor features do not work when it comes to copy/paste/undo/cut.