This happens sometimes -- and there are various reasons for it.
The most common reason is that the topic (or post) has been deleted. To delete a topic, the topic has to be moved to the trash, followed by the links being updated to no longer show the topic/post existing in the forum. Unfortunately, due to race conditions, it is possible to have the page, with the old links. And when you click on this outdated links, you get the "not enough privileges" warning.
In other words, I wouldn't worry about. There are reasons why the topic has been deleted.
Joined: Sep 01, 2010
Thank you Henry for the explanation!
I can see from the contents of this forum, and a search on the term "privileges" that this is actually a pretty common occurrence.
May I suggest that something like the following line be added to the header section of the "Work Offered" forum:
Job postings that do not conform to our requirements will be deleted. Users who try to access posts in the process of being deleted may get the following error message: "Oops. You don't have sufficient privileges to see this post."
Alternatively, rewrite the error message to convey that there is a deletion in process.
It could save a number of aggregate man hours, both for people puzzled by the error message who search for answers or end up posting to ask why, and for the forum leaders who answer the questions.