This is an interaction with the Blueprint Shotgun "https://mods.factorio.com/mod/blueprint-shotgun" mod. I suspect it's a bug in that mod, but I'll report it here too just in case.

In the attached save, at [gps=1049.6,1659.7] I have a red miniloader in load mode marked for downgrade to yellow miniloader. If I shoot the blueprint shotgun at that miniloader to try to downgrade it, the miniloader turns into a glitched building. The glitched building looks like a red miniloader, but I can't mark it for destruction or upgrade, I can't mine it by hand, I can't open its configuration popup, I can build a small power pole or iron chest over it, and it no longer loads items into the big chest. I don't see a way to remove this glitched building without cheats.

Save: https://drive.google.com/file/d/1D0zN0n3ODJIq1T0Dss-mmLi39dgOHwxt/view?usp=sharing

Versions: Factorio 2.0.67 (build 84451 expansion, linux64); Blueprint Shotgun 0.2.20; Miniloader (Redux) 0.13.0

Bug crossposted from "https://mods.factorio.com/mod/blueprint-shotgun/discussion/6a0dda58a58316fd9af3120a/edit/0"

This might be the same problem as with blueprint sandbox described here: https://mods.factorio.com/mod/blueprint-sandboxes/discussion/69f987c16a415897c8875d6c

If a mod does not use the "right" way to manage upgrade/downgrade, then Factorio does not fire the right events and you end up with an incomplete entity. What you see is actually a piece of a miniloader (either missing inserters or the loader) that was not fully constructed.

This is tracked here: https://github.com/hgschmie/factorio-miniloader-redux/issues/40