Helix 12 jumping all over

I have a Gen 2 Helix 12 that has started giving me false depth readings. I can be setting still or moving and it will jump to  some random depth or two or three and then back to about what it should be. Makes it sorta hard to map anything when you have 60' holes on a 12' hump. Any ideas on what is causing this? The transducer is located on the back side and appears to be at the same angle when I installed it. It worked fine for the last two years now it is of no value.

Thanks for any ideas on what to look for.