We have 7965G phones connected to Jabra Go 6470 headsets with the EHS plugged into the AUX port. Phones will occasionally freeze and the screen is off completely; they remain in this state until the AUX cable is unplugged and the boot process starts immediately.
The switches sometimesshow PoE alarms, but not always:
%C4K_ETHPORTMAN-3-INLINEPOWEROVERDRAWN: Inline powered device connected on port <interface> exceeded its hardware protection threshold.
It sounds like a bug. I'd try on the latest firmware version then try going back to some older firmwares and see if the same behavior is present in all versions. You might want to ask Jabra which firmware version they tested with. Jabra has an agreement to have direct access to Cisco developers for this kind of integration testing.
Good pro tip on the Jabra relationship. I've pinged them again to clarify firmware version(s) supported or tested.
At what level of the phone logging am I able the debug this particular interaction/behavior to see if there are any alarms? No alarms are present on the phone's webpage logs, and the /FS/cache logs are useless here.
You can set up SSH on the phone and the log in to turn on more extensive debugs as necessary. It's difficult without developer interaction to understand what debug options are important for which features on these older model phones.