A meridian flip is not a specific command to the mount but it simply re-issues a slew command to a target that has crossed the meridian since the last time it has been slewed to.
-Wolfgang
To expand on what happened as I don't have logs. I would be tracking the object for a few minutes, it would pass the meridian, pass the constraint I set, capture would finish. Mount would slew and plate solve. Sometimes it only slewed a few degrees, once it flipped, plate solved and flipped back.