Changing log times using tshark

Hi all,

I have been running tshark on a clean ubuntu server for a few weeks, but i've noticed something odd in the timestamps of each logfile, while i setup the duration to be each hour..

for example:

Nov 19 04:05 example1.cap

Nov 19 05:05 example2.cap

Nov 19 06:05 example3.cap

Nov 19 08:59 example4.cap

Nov 19 09:59 example5.cap

As can be seen there´s a time gap between example3.cap and example4.cap

This is the command i've been using: nohup tshark -i eth0 -t ad -w /var/log/filename.cap -b duration:3600 &

I´m worrying about this since there are specific random network problems appearing, because they might happen in these gaps..

Does anyone have an explanation for this, and what i should be doing=