Hi Frank I am experiencing a similar problem. The mca files display the correct icon but 'get info' displays nothing. The same files work correctly on my phone (Android 6.0.1) using OSM . However my tablet 7.1.1 only shows icons using either TomTom truck maps or OSM. I have emailed Tomas who does not see that what I describe is possible. Now there are two of us with similar symptoms.
I can't reproduce this issue, in Qtdigger I tagged name and showonmap. But ok, I admit that the discription cannot be seen in all zoom steps. When invisible, I have to zoom a little in or out and the description exactly appears where you would expect it due to your digger settings.