VERY WRONG directions from Navigation in Yellowstone N.P.

When Navigating from Old Faithful Yellowstone N.P. to West Yellowstone, MO the navigations directed us to Mammoth Springs and up to Gardener MO. – Hundreds of miles out of our way. 191 goes out the west entrance and fortunately we had looked at some other maps before following the Navigation..
We tested the Navigation by programing it from the river road a few miles from West Yellowstone and the programing still directed us back to the Madison River area and told us to drive over 3 + hours by going north to gardener and around west and back down south to West Yellowstone as if the road was closed or something. The road is very busy and very open.