No it doesn’t.
I don’t think it would actually move us any further forward, but the ‘void’ state for an Item is either NULL or UNDEF.
NULL usually signifies the Item has been reinitialized for some reason, while UNDEF is generally what a binding should set to indicate “unknowable” because there was bad comms or suchlike. So it can be useful distinguishing which exactly.
However I would not like to assume v1 MQTT binding follows these guidelines. Your events.log should show you what is really going on, but I don’t think it helps.
This thread covers the same ground