Where I downloaded 4 maps, 2 Ontario and 2 Quebec maps. One is “new style generic” and the other two are just generic. One of each map.
After installing onto my device, I can only access 3 of the 4 maps. Also, when selecting the “new style generic”, no changes happen to the map. I just see a blank map with my location and a few other pins, but no map information. The same as having nothing selected.
I’m big into hiking. It’s the reason why I got this watch. I’m not interested in roads, etc, but more terrain based maps, good for hiking, which is why the “new style generic” ones are so much better for me.
I am not familiair with the fenix, but the new style is using a typ file, which may be the reason that it might be incompatible with your device?
You can look at this website from user “popej” who makes maps for the Fenix: http://www.gmaptool.eu/en/content/maps-garmin-fenix
Actually my maps for fenix are very simplified. They were designed for fenix 1 and 2. Fenix 5x is much better device and it fully supports maps. You should rather use detailed maps for Garmin, like the one form http://garmin.openstreetmap.nl/
All that said, I don’t know what the reason for the problem is. I would think, that maps should work flawlessly.