Yes, it has the potential to be your issue.
Click the Remove button, once. It will appear as if nothing happened.. this is because that button mostly just sends the command to the Radio and let's it do all the work, behind the scenes. If the device completely doesn't exist, then the radio will detect that and delete it. Hubitat will detect THAT and delete it from the list.. some time in the future.. probably no less than 2 mins though. Which is why it looks like nothing happened.
After 5 mins, give that page a refresh and click the remove button again, once. Repeat at no less than 5 min intervals. If you had a Zniffer you'd see the 'storm' of packets related to the attempted removal, making it clear why a 5 min wait is best. I have Zniffer, and thus am able to offer this advice. 
The critical thing to understand is that the Radio begins the Removal process by 'pinging' the device. Far too often it determines the device is responding and that terminates the Remove process. A 2nd and even a 3rd attempt by you and me will eventually convince the radio that we are serious and it will grudgingly detect that the device is not responding and THEN do the actual removal. (More technically, radio's using cached info that fools it into thinking the device still exists.)
