Summary report showing negative Min value

Hi,

I am using JMeter 2.11 with Windows.

When started a non-GUI test I was surprised that summary report showed negative value for Min.

My test script is quite simple.
-start 100 threads with some initialization tasks
-synchronizing timer
-threads perform looping some "typical" http actions: GET, POST, DELETE

2014/08/08 06:53:00 INFO - jmeter.reporters.Summariser: summary + 2329 in 7s = 343,1/s Avg: 21 Min: -207 Max: 1363 Err: 0 (0,00%) Active: 100 Started: 101 Finished: 1

Is this a known issue?

Regards,
Keijo