Logging '1.2.5 Unhandled exception in ASP.NET' for errors that have been handled

Description

Steps to reproduce
1. Create a new Episerver Alloy website project.
2. Replace the project source files Global.asax.cs and Controllers\DefaultPageController.cs with the modified versions that use Server.ClearError in Application_Error.
3. In these two files, replace occurrences of the string "EpiserverSite2" with the project name for your Alloy website.
4. Build and run the website without debugging.
5. Once the website loads, click the "About us" menu option to navigate to the about-us page. A blank page is displayed.
6. Refresh the page a few times so that the exception is logged more than once. The about-us page continues to display a blank while you do this.

Expected: Shouldn't log handled exceptions.
Actual: In the App_Data\EPiServerErrors.log log file, you see '1.2.5 Unhandled exception in ASP.NET' logged multiple times with no stack trace being logged.