I have the same problem. I have a sub-account that I have not used in about three months. When I was using it, I noticed that my FP (Bronze II) got stuck and would not promote or demote. There is only one other person in my league. The other player has four times as much power as me, so I can't beat her. There is no timer, so I can't be promoted or demoted. The status message says "waiting for more people to join" After reading this topic, I logged back in today for the first time in about two months, and nothing has changed. No demotions for inactivity, no promotions for being in top five. No merges because our league is too small. Just stuck.
No, I haven't reported it. Like I said, this is not an account I play on, so why would I waste my time ?