Do you know this as a bug ?
Take some model with a zone of needed bridging.
Set "External infill pattern" to "Rectilinear" => Nice slicing with normal bridging
Switch to "Concentric" => The bridging condition is not detected. A concentric pattern is put in mid air instead...
Workaround : place a special process with "Rectilinear" external infill on the layers surrounding the bridge.