I'm having issues with a "Ghost finger" on my GPS page. Its basically takes your location away from the boat on the GPS to a random spot on the the GPS map as if you touched the screen. It's a major nuisance when running. Garmin support suggested running an additional ground wire from the silver metal connection on the back of the unit. I'm skeptical of this solution and wanted to ask of it was something I'm missing in the settings before adding the secondary ground wire.