Problems with logs

I have the latest version of Mission Planner 1.3.28
Flown with my octocopter 3.3 and today 3.4 dev

For some time there are no readable logs when using USB connection and download with mavlink.
The date of the files are correct, the times in the log are 2014-12-17

Removed the SDcard and put it in my computer
When I open the latest log all time stamps are 0001-01-01 00:00:00.000
If I click the field it changes to 2014-12-08 13:40:46.711 The time is exactly the same from top to bottom but the log should be about 20 minutes

Any idea what causes this?


By unreadable I’m referring to the “Value Graph” in the Log browser.