This sounds like you're using a mod, or some custom lua. Or maybe even a bug in the save migration?
Because they definitely don't get coloured in my version of factorio.


It could be some shenanigans with the save migration, and it can blueprinted!

this is a white cargo wagon, and it will not ...

What did you do?
marked a roboport for deconstruction.

What happened?
It didn't stop requesting bots delaying its deconstruction indefinitely

What did you expect to happen instead? It might be obvious to you, but do it anyway!
I expected to stop requesting bots like a buffer/requester chest do ...