USB port malfunction with Garmin GPS?

So I plugged my Zumo XT into the USB port on my '22 Classic 350 for the first time, and heard a pop from the battery area. Fuses all look fine so I took a ride, about 20 mins in the engine started "surging" at idle, and a message started flashing up that looked like "CH9BAT". I could find nothing online and my local RE service dept never heard of it.

Never had any issue routing the Zumo through cabling to the battery's charging pigtail cord to power it.

Thoughts? Thank you!!