I can't see what's different since your post has not words about make, models, settings, firmware version...
I know this is pretty much the same thread posted but I wasn't sure if it is exactly the same problem. I've experienced my connection going out and once I go back to my settings of the network the network authentication has changed from shared to open and I'll have to reenter my network key. Once the connection is lost it also switches to another network but isn't connected to the internet at all.
Suggestions or answers please?