Yesterday, I had to change my router (hurray, I've got Fibre instead of DSL-Copper).
Switching back to direct mode was not the problem, but switching back to Stationary mode. The S50 couldn't see any 5G network. First, when switching to 2.4G, I could see my router and all other router in the neighbourhood.
While doing this, the router and the S50 were 3 meters apart.
I can live with the current situation, but just for the case, somebody experience the same.