I am experiencing the same issue. According to the list, I am eligible for 3 posts per day. I was also able to make these 3 posts on a single day in the past.

However, when posting on consecutive days, I can often only make one or two posts (in the regulated areas; obviously not counting unregulated forums). Check my posting history:

01.09.: I didn't post
02.09.: locked out after three posts
03.09.: locked out after two posts
04.09.: locked out after one post
05.09.: This is the only post I've made today, and I had to wait a long time for it. Why is this forum regulated at all? It's a bug report forum!