Gen 1 Helix 10 at the bow. Gen 1 Helix 12 at the console.

Starting 1 year ago, the bow would read about 5 degrees warmer than the console.

Starting about 2 months ago, both units would read an appropriate temperature in the morning, but would actually start reading cooler into the afternoon. For example, this past Friday I was out. They were both reading 82-85 degrees in the morning, but by the time I got off the water, they were reading 72-73 degrees. No, I was not fishing water that should have been 10 degrees cooler.

Any ideas on what's going on and what I can do?