When a post a new thread and choose to subscribe to it at the same time, the subscription doesn't stick.

I have no problem adding a subscription to a thread that already exists.

So if I want to subscribe to a thread I'm starting, I need to start the thread and then go back in and add the subscription.

Strange bug I've noticed for weeks now, actually. For the first time today I checked the number of threads subscribed to before posting the new thread that I also wanted to add as a subscription... after posting with the selection to add the thread, the number of subscribed threads remained the same. After going back and adding the subscription later, the number of threads subscribed to increased by one.