Whenever ASP.NET reports a dangerous query string value to the Application log and the request contains a certain combination of characters; the event viewer will not show the error information and only shows 1 or 2 special characters. Clicking through to the Details tab shows all of the error information correctly.
An example of a ASP.NET request that causes the behavior: http://localhost/default.aspx?modpagespeed=off%22%3E%3Cstyle%3E%3C/style%3E%3Cdiv%20style=%22display:block%22%3Eplease%20click%20%3Ca%20href=%22http://localhost/?modpagespeed=off
I'm posting here as the behavior is expected from ASP.NET; but should I be concerned about the display errors on the General tab of the event viewer? This is reproducible in our test environment. Also, the special characters displayed are different each time the event is opened.