La batería se agota

I plugged the T-Mobile sync up in my 2017 Cadillac CT6 and left it there. On the next start several days later, a message popped up saying to check the charging system because of a low battery. I had changed the battery a few months before but I took it in to the dealer and they said there was no problem with the charging but the battery seemed bad. AAA said the battery was good. As a precaution I removed the sync up whenever I don't need it. I've also used this same sync up in a 2021 Buick Enclave and a 2010 Suzuki Grand Vitara without a problem but I continue to remove it when parked overnight.
Has anyone else had a car battery drain while using a sync up?