locked OSM cards in edge 1040

I render my maps from Openstreetmap data and have use them in Basemap (v4.7.5) no issue with the maps here.

If I install the maps on the edge 1040, it happends randomly that one ore the other of them are locked. Same if I copy the gmapsupp.img directly to the device (with different card names, for sure.)  does somebody has an idea why the edge 1040 locking my own maps and what I can do to unlock them?

regards

Dieter