I have a new home (constructed 3 yrs ago) that has an arc fault breaker that runs the guest bathroom and one bedroom. Almost never use the guest bath and the bedroom has had no change in electrical use for the 3 yrs. 3 months ago the breaker tripped 3-4 times in a row with no explanation and then would not reset. Installed a new arc fault breaker and it worked fine, however issue now is that every 2-3 weeks it will trip whether I am in the bedroom/bathroom or not. Have checked light and light switch in bedroom, didn't see anything weird. Maybe bathroom fan or light? It has tripped even with nothing on in bathroom too. Any suggestions on where to start?

Electrical Supplies - Eaton - 20A ARC FAULT BREAKER