Sforno on Numbers 9:19/ספורנו על במדבר ט׳:י״ט

1. ושמרו בני ישראל את משמרת ה', the reason why the Torah repeats this fact a second time is to emphasise that even when the location selected by the cloud was not only inhospitable, but the cloud remained there for a long period, the Israelites did not grumble or protest this fact. They did not start journeying on their own, looking for a more suitable place to encamp.