I've been chatting with Discovery about the same issue. Again, they say it's a known problem and are working on it.
Originally, when I signed up for the service I chose the ad version. Personally, a 60-second ad every 20 minutes doesn't bother me. But, yesterday, I changed the service to ad-free. Last night, the problem went away. I was a bit upset, to say the least.
I emailed back the technical support staff and told them what I had discovered (no pun intended). I made it very clear that if multiple services are offered, the software should work for either one. And, that the fix should not be paying more to rectify an issue with the software that should have worked at launch.