pipeline pause and timestamp

[mattes]

I have a capture/encode pipeline. To pause the pipeline I use:

    gst_element_set_state(pipeline, GST_STATE_PAUSED)

After specific time I elect to resume and call:

   gst_element_set_state(pipeline, GST_STATE_PLAYING);

and my capture/encoding is re-engaged.

One thing I noticed, there seems to be a difference in how that effects
the timestamps.

If I pause the pipeline e.g. for 10 sec and then resume, the timestamps are
roughly speakings advanced by the length of the pause. 

In case the pause time is 60 seconds or longer, this is not seem the
 case any longer. It looks like the timestamp got frozen during the pause
period. Time stamps are only advanced by ~45 seconds after resume.

I assumed that in pause mode the internal clock actually keeps ticking.
But that seems not to be the case.

Is this behaviour normal?
What can be done to keep the internal clock running (or timing out)?

Is there a way to reset/set the clock/timestamp?

Mat