It can be both, but the situation when CodeProject servers are overworking happens from time to time. Sometimes it results in double posting: CodeProject reports that it cannot complete a post, someone posts again, but page refresh shows that a post actually happened in first place.
Please post your observations, too, maybe you came across some different cases. Load
http://www.codeproject.com/Forums/1645/Site-Bugs-Suggestions.aspx[
^] and click "New Message".
—SA