Water Boundary Issue - Missouri River Near Jefferson City, Missouri

Hello. I’m new to this forum, and OSM in general. I’m using the maps from garmin.openstreetmap.nl, which are based on the OSM data.

I use Garmin’s Base Camp on-pc map management system, and use a Garmin Dakota 20 GPS for the maps. Everything works fine, save for this:

The following links show both detailed and less-detailed views. I know this has something to do with polygons, but as I’m still learning, I’m not quite sure what to do here. The display problem affects me locally, so I’d like to fix it if I can. I know the Missouri River doesn’t go that far north.

Here are the links, which are screenshots from Base Camp:

http://www.panoramio.com/photo/72790350

http://www.panoramio.com/photo/72790355

I’ve also posted this here: http://forum.openstreetmap.org/viewtopic.php?id=16807

Moderator: Please consolidate this if you feel it best to do so

Sincerely,
Stephen/Firefishe