Axiom 12 chart shading

[TEV]

I have an Axiom 12 with current Lighthouse and Navionics loaded. This last weekend this T shaped area of the chart was displayed. I have gone through the settings and cannot find where a setting can be changed to remove it. Prior to this the entire chart on the display was bright like the T shaped area. Any ideas or suggestions where to look or disable a setting I may have turned on?

[TEV]

Update, talked to Navionics rep and unbeknownst to me the Navionics on my iPhone had synced with the plotter (I turned off auto connect). The area highlited I had downloaded the most current chart info onto my iphone. When it synced with the plotter it brought in updated chart info for that highlited area only. So they recommended I take card out of the plotter and do an update.