Just an update on this.. I misspoke when saying it was a bluetooth issue. The phones in question (5360) have the DECT Module in it. What seems to be happening is during a call, the Dect Module blue light will turn off, the call seems to still be active (the user in question believes if she hits the speaker button, the call will resume on the speaker phone) but the Dect module, and or communication goes dead.
We have changed phones, and the same thing has occured. Its not on every call, but it happens enough to be not trustworthy when on the phone and is causing the user to use her cell phone for calls. I have put a corded handset on the unit today and unpaired the 2 dect devices (handset and headset) to at least make the unit trustworthy to use.
The question is what is interfering, or why is the dect module dying? There is no wifi inside her office that can be the issue.. (I have global wifi in the office and no one else has dect issues, including myself whos sitting right on top of the wifi router basically).. Her iphone 8 is there which has wifi on, and standard pc equipment, printers, scanners, monitor etc.. Its Crazy.