I have this problem that returns periodically.
The phone of the operators console will ring continuously and will also sometimes have its call keys get stuck on as though there is a call on the key.
The ringing part, I believe I read a fix for it but I can't find it now, searching for "console ringing" or Mitel 5000 phantom ringing", given how common my search terms are.
There are 2 systems networked together that the console is for.
I'm just wondering if it rings a bell with anyone.