The other half of the garage is wired into the bathroom outlets.
That is not uncommon. I had one GFCI outlet in the main bath. Then the wires went to the master bath outlet, then to the
single outlet in the garage; all on one 15amp breaker. I've been told on the GJF that was "code" 20 years ago when the house was built. Today, not sure if its code or not.
The right way to have done it would have been to put the two bathroom outlets on a single breaker (one of them GFCI) and then the garage on its own 20amp breaker with the first one in the garage being a GFCI.
OR ... rather than a 15amp breaker for two bathrooms and the garage ... use a 20amp breaker, proper wires, and proper outlets.