Posting in "open" forums eats up the new posts/new threads allowance

I honestly consider this a bug. This forum is already punishing paying customers enough with all its limitations. Now I've found out that in order to post in the limited forums I have to do it an advance, before to post in forums like "New player".

For example if I open one or more threads in that forum I couldn't open this one, as it happened yesterday.

My web browser is Safari 6.0.5 on OSX Lion. Not that it really matters since this is server related.