When I try to parse date like this:
DateTime t1 = DateTime.ParseExact(\"August 11, 2013, 11:00:00 PM\", \"MMMM dd, yyyy, hh:mm:ss tt\", System.Globalization.
I was hit with this too. In my case, a UI automation test failed because IE seems to add this LRM (Left-to-right) mark automatically (Firefox and Chrome do not). A quick line of code that strips it away:
Regex.Replace(date, @"\u200e", string.Empty)