Set the Ping Rate to 16 and see if that fixes.
Then I would back-up my Waypoint,Routes&Trails and Settings.
Next, I would perform a Soft Reset(Note this will NOT DELETE GPS data). See if that fixes.
Next, I would perform a Hard Reset(Note this WILL DELETE all GPS data). See if that fixes.
Next, I would swap console/bow units, and see if problem stays with unit or transducer.