Yes, Skymaxx Pro v5 to display the clouds, but I'm using the X-Plane real time weather.
I believe now that it must have been something with real time weather or rather the display of it, as it happened 3 times in a row and at the 4th time with a weather preset of X-Plane (same route) everything was ok.
I can try again with real time weather later, as now the weather is different. As I remember, it was stormy when RAM issue occurred.