I had a request for a new medical despite sending one in upfront. Even though the medical was expired by about a month by the time they sent the request, I was sure that they would be able to accept it. I wrote a CSE and attached the existing medical and an explanation letter. Did not get a response. CIC phone agents weren't able to offer any guidance (except for saying that nobody had read my CSE yet). The 30 day window they requested the new medical also had expired and I hadn't heard anything from CIC.
But, as it turns out, I made the right choice and they must have looked at and accepted my medical all along because they just sent me a landing letter. Landing next week. Awesome, saved a couple hundred dollars on a useless medical.