[PC] Microphone Opening Unintentionally

I’ve been playing Battleborn with a group of friends and we exclusively use Mumble for voice communication. I do not use the in game voice chat to talk to them, but the voice chat seems to turn itself on periodically for no reason and stick open. I notice this happening a lot after death. Cycling my in game voice to chat (bound to the End key) disables it. I am not hitting the in game voice button at all during play and it is not an issue with my keyboard.

I’ve tried to disable in game voice transmit as a work around, but I was unable to find a setting to disable it.