@ATLast
I reply to my own post.
I finally unistalled the program, made sure I wrote something on the recovered space and installed the program back: both problems have now disappeared and that part worked fine today. Wich however questions the update process as the app was installed 18 months ago when I changed my phone...
I tried it again today, ran into other problems, solved by switching off the bike, the app and Android Auto, but I also noticed how the program has improved when reaching a blocked road (which is common in Belgium): it searches a new route and doesn't send you back to the blocked one. Great job!
Bye for now.