TwoNav Cross+ totally crashed

Total crash of my GPS TwoNav Cross+
I connected the Cross to the Windows PC and copied a waypoint file to the PC. 
Afterwards I had to quickly get away from the PC. When I came back I found that the PC had gone into standby mode. 
So I activated the PC again. I then unplugged the cross. 
The cross crashed completely. I noticed this because it didn't switch off as usual, the backlight stayed on. 
I tried turning on the Cross using the buttons. I noticed that it no longer responded at all to pressing of a button. 
Even pressing the power-on button for about 20 seconds didn't help. The Cross was dead! 
I had no choice but to wait until the battery was drained by the backlight (the lighting switches to dark). 
This was the case after about 1 day. I then connected the Cross to the charger again. 
When I did this, it lit up red, started to start, then just shut off, started again, and so on. 
I left it on the charger. After about 20 minutes I unplugged it from the charger and tried turning it on. 
Lo and behold, it could be switched on. It worked perfectly again. No data was deleted either. 
To this day I still don't understand why the Cross had a total crash.
Maybe this report will help someone in the same situation.
→ Let the device battery discharge until it is completely low (lighting switches off). 
Then connect it to the charger again and let the battery charge.