Upgrading to 6.14 worked for me... But...
Some of my friends still reporting me that timestamps are wrong after upgrading to 6.14... They all use win2k . I sent my mirc.exe just to compare executables -- no differences found. Then one of those guys restarted his mirc(several times), and the bug disappeared... Pretty strange. Anyway , again, upgrading to 6.14 worked for me.

So i advise to everybody suffering from this bug to download newest 6.14 version and double check that after upgrading they are running 6.14!