I'm not firm about how z ordering is implemented in factorio map view, would "simply adjusting the z index" potentially introduce issues?

1. open map
2. activate rail signal states
3. select a copy area
4. rail signal states appear on top of the copy UI instead of behind (as the rest of the map)
factorio rail signal states.png

Edit: the same applies for station names. Also if the list of items is too long, it can go off-screen ...

Copying a 8x8 beaconed electric furnace design resulted in a blueprint containing a furnace with 3 modules assigned to it.
See also screenshot and attached blueprint code export.

The bug appeared in the attached save file in multiplayer: copied the leftmost column of electric furnaces of iron ...