Descent Mk1 Map problem

During an activity, remaining on the map screen, after some time the map "freezes" and doesn't load the map anymore (blank screen, you can't even see the recorded track) and stop rotating according to my track. The only way to temporarily solve the problem is to change to a data screen and then go back to the map, forcing it to reload, but after a while the problem reappears. I have contacted the italian support, I have sent to them clips and pictures demonstrating the problem, I have sent the device to the support and they told me that everything is ok for them..... Now I got it back and the problem is still there... Simply the support doesn't care. I also reported that the spell name search for poi (expected function according to the user manual) doesn't work for most of the categories, the device starts the search but never ends it. Again they told me that for them there are no malfunctions founded. Shameful attitude. I feel like the support is kidding me. I hope somebody from Garmin will look at this post. Firmware version is the latest available in italy, 2.20. Anybody using the Mk1 for activities like hiking noticed this problem?