Hi JasonPettty,
Back in February 2015 I encountered something similar on a 5312 IP Phone (System was on 6.0.9.61) whereby a user would have 2 Call Keys and the 2nd call key would flash, even though no call was on it. It was never determined what may have brought it on, only that rebooting was a temporary fix as it would usually come back. I opened up a ticket with Mitel on it who said:
<Begin>
"This was an issue which was believed to be corrected in a later release but the problem has returned to some sites and we are currently investigating it. Upgrading this customer's site may correct their problem and stop it from returning, or the problem may return in the future, I cannot say for certain. I will leave it up to you and the customer whether or not you want to upgrade them now or wait until the next fix is releases (I currently have no time frame for that release)
To clear the key from the phone you have two options
1) Delete and recreate the extension
2) In a keymap, program the stuck key as another type of key, reboot the 5000, and set the key back to a call key again."
<End>
I opt'd to upgrade the system to the latest version at that time which I believe was a variant of 6.1, after that the issue never returned and has since undergone another upgrade to 6.2. I have never seen the issue since.
Hope this helps.
Thanks,
-Iron