Lasagna is a major point of dissension between my wife and I. I prefer layers of pasta/ragu/mornay sauce, but her family have always added cottage cheese. The result is rather strange, but not entirely unpleasant. I believe in her families case it comes from the Welsh valleys where Italian immigrants (mostly running the local ice cream parlors from what I understand) couldn't get mozzarella to add to their lasagna and made do with the closest local cheese they could find. Their neighbours thought that was how authentic lasagna was supposed to be made.
There is a separate story to be told about the time her mother accidentally bought cottage cheese with pineapple chunks in ti and decided to go ahead with the lasagna anyway!
I'm from the UK (not the Welsh valleys to be fair) and I've never heard of cottage cheese in lasagne before this thread. It's certainly not in any recipes I see here.
They are a strange lot in Wales though, so who knows