The current, correct map from NPS

Some GPSs use OpenStreetMap as their source of truth. This includes traced trail routes in addition to terrain.
OpenStreetMap appears to be accurate for Isle Royale, with the exception of the section from Windigo to Feldtman Lake. These trail traces appear to be from the time before that trail system was changed a number of years ago. The trail out of Windgo cuts too far away from the lake after Grace Creek, and it connects with and also displays a no longer maintained trail that passes on the east side of Feldtman Lake.
OpenStreetMap presented Trail Traces that are out of date The Yellow highlighting is unmaintained/out of use trails. The red arrow points to the area where Feldtman trail actually goes today
If you want to verify if this affects your GPS, look at the west side of Isle Royale, it should look like the top map and not the bottom.
Paul