I bought an M600 a couple months ago and it worked great the 1 time I tried it. I noticed the app looks a little different lately but didn't think anything of it because it was a little cold to use the pool anyway. I recently turned it on and it is terrible at cleaning the walls and waterline now. It also doesn't come to the surface when I use the pick me up option. This wasn't the case when I used it a month ago. Anyone else noticed this or have any suggestions?