Elapsed time is reported incorrectly for tests run in parallel

Configuration:

<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.16</version>
<configuration>
<parallel>methods</parallel>
<threadCount>2</threadCount>
</configuration>
</plugin>

I am running a suite of JUnit tests in parallel with the above configuration. The "Time elapsed" reported after a test class is incorrect by a factor of the number of threads in use.

In my case, I am running tests on an eight core machine (see Environment), with two threads-per-core. The actual elapsed time is about 47s, but the reported elapsed time is 741s.