In using my HB 859 DI yesterday , I ran into an issue I've never had. I had previously marked waypoints that I was moving in on to fish. The waypoinjt dots were jumping all around on .me. They would show to be 100 foot to the front and right of my boat position and as I approached them, they would suddenly show to be directly behind me 50 feet, then the chart would spin and they would show to be 100 foot to my left, the maybe 200 feet to the front and left, etc. Everytime I tried to approach , they would shift around to places on the lake that I knew were not correct. For example, I was trying to fish a channel that I know is about 250 yards from the bank, but the waypoints would keep moving around to maybe 100 yards off the bank, then move back to about where I know they are supposed to be. Another thing I noticed was that my little red boat icon would change to a round red circle and it appeared that when this happened, it would stop tracking where I was going for a while and then the boat icon would reappear and start tracking again. Any ideas ?

Another issue is that I was trying to change the digital readout boxes. I went to Advanced mode and Setup screen and would select the way I wanted the boxes to raedout, but when I would exit the Set up mode the digital readout boxes would stay the same as before. Is there something I should be doing to Save my selections? I can't find any Save method from looking at the owners manual.

Any help appreciated......