This home I inspected yesterday, the circuit is on a AFCI breaker, labeled on the box as “smoke det’s”
The white wire from the breaker is not connected, just comes off and is terminated with a wire nut. The smoke detectors work and all bedrooms have power. Any thoughts?

The AFCI breaker will not function as intended unless its neutral is connected to the terminal bar.

Yep. Breaker will work like any other Overcurrent Protection Device but as jeff stated the AFCI feature is not going to function.

Couldn’t agree more.