I have a MSBuild project that batch processes a list of projects and I have the task set there to ContinueOnError as I need all the projects to be compiled.

In Jenkins I DO NOT have the Plugin configured to Continue Job on build Failure.

During build an error occurs but the failure is not Failing the build when MSBuild is done and returns to Jenkins the Plugin is not failing out.

MSBuild is reporting 12 Errors on exit but the plugin just lets the job continue, job status at that time is also not Failure. 

These particular errors are somewhat unusual as they are from Postsharp and have a line that beings like this:
20>unknown : error : error: Unhandled exception
Not sure if that is the issue or not.