I know that I'm in the Overflow
It shows up because it’s not immediately obvious that you’re in an overflow, which is relevant in some circumstances.
Mainly for when you’re leveling a craft.
They should still make an option to cancel the display of that popup – default to showing it, of course – so that those of us who don’t mind/care won’t have to deal with it, and can simply check the minimap to see if we’re in one or not when it becomes relevant to us.
The queue could also have its own option to always decline or something.
It is pretty annoying I would love an option to disable it popping up.