Remove Zeroline around island that doesn't exist?

I'm a brand new Autochart Live user.  I've just started making my own maps, but I have a problem with the base Lakemaster map.  It has islands that don't exist.  It's not just a depth problem, some of those "islands" are easily 10-20 feet below the surface.

Here's an image showing my imported logs before I map, clearly I drive my boat "over land" here.




After I create the map:



And Lakemaster:



So?  How can I remove these ghost islands?  BTW, this is a large river... creating a custom shoreline would be time consuming.  Can I not just force Autochart to ignore certain zerolines?

So, an update.  I contacted Hummingbird customer support and I was informed there is a setting to disable shorelines when generating the Lakemaster contours.

The trick is, to map a very specific area around the ghost island with the "shoreline" setting OFF, and then map small areas all around the ghost island with the shoreline setting back ON.  That did the trick to get semi correct depths (for the few passes I did).



And the result:

Nice, thanks for the info.
Too bad you had to answer your own question but these things are complicated.