This one I can answer myself

....
I used the
observer for a 1,5 year now and by coincidence I saw there were cracks on the inside of the
strap 
. Some of them are deep already.
Of course i returned to my retailer and he will discuss it with
Suunto. My retailer said that this should not happen with this kind of polymer. So i will wait and see.....
regards,
Ernst