Mine seems to do the same thing…but only on vertical zoom. Anything less than 6fow or so and the vertical zoom “flashes marks” and shows depths much greater…it goes in and out, one second it’s fine the next it flashes interference for 2 seconds or so. I have the normal circle flasher on as well and that shows my jig & correct depth without any issues at the same time. Like I said it seems to be associated with the vertical zoom only as any other setting the “flashing” does not exist. Weird???
I should add that with the latest update I can see my lure much higher in the water column when fishing shallower water…night and day difference from last year. 