You know, I do not have your model, however, we have had some leaks. Once I do not think ANYTHING could have been done to prevent it. We were in Amarillo, TX and the wind was blowing so hard and the rain was coming in buckets. We got rain around two windows simply because the drains could not drain fast enough. The other time we had a leak was, I think, partially my own fault. We were in a campground and not really as level as we could have been. We had some hard rains and water was coming in at the TOP of the slide because we were not level.
I do think that all you can do is level up as best you can, make sure all the slides are sealed as best as they are able, you will stay dry. However, taking a look at all of our units, they do not seal totally so there is always a potential for leaks.
If you are seeing daylight around a seal, that is a different story and should be fixed. I can say that despite our leaks, I do see daylight anywhere.
2013 Infinity 3640RL with Trailair pin box
2008 F-250 King Ranch Power Stroke diesel with B&W Companion Slider hitch