Extra device showing - what does this mean?

On my pull down menu on the “now playing/not playing” icon widget thing - there is an extra iPhone name/device and I don’t why or where it’s coming from?? If I click the unchecked iPhone - it looks like they merge, but it goes away - it will only show one device for a long while and then it just pops back up?? Please help - and there is not another iPhone here either