Rear Brake Issue

I'm starting to have problems with mine again (2020 GT) after the recall replacement. I need to call them and have them do something about it. Rode 2 days ago and it was fine. Went out this morning and had almost no rear brake and the res seems.. low, yet I don't have any brake fluid puddles anywhere on my garage floor and it certainly didn't soak in and disappear because it's an epoxy coated garage floor.