This message comes as well when the forum logs you out and you try to post in a thread.
When you check the "Remember Me" checkbox, you can prevent this from happening for those cases. Other then that, certain sections have post restrictions, such as constructive feedback as well as bug section, which will be something we will explain in our forum guide, which is currently in the works.
So to clarify if this was just one of those sections or might be another flaw in the software upgrade that needs our attention, please be more specific where exactly this message occurred.
So to sum it up: Yeah message is misleading and kudos for not assuming that we did that on purpose :p