I am experiencing the same issue on my dm8000: PTS works unreliably when shifting over more than one event. Plus, 'timeshift record current event / select event' leads to a recording with length 0.
Problems started when I did an update somewhere early January 2012. It was my first update in at least a month. During December, I didn't see the problem.
Today I uninstalled PTS and installed an older version of PTS from early December (I tried 10/12 and 4/12). But 'Timeshift record current event' again lead to a recording with length 0.
I do remember something was changed late December in the way the timeshift buffer operates. Maybe that has something to do with it.
In the enigma2 update log, I found the following information:
Record stream information during timeshift - Mike Looijmans [Sun, 25 Dec 2011 11:02:12 +0000]
servicedvb: Record stream information during timeshift
Write an sc file during timeshift. This allows smooth (re)winding
at >16x during timeshift, and also improves skipping and other seek
related actions.
Drawback: The AP data is stored in memory, consuming ~64k RAM per hour
which is not used for anything.
Could it be that the PTS plugin is not aware of the changed timeshift structure and therefore cannot record it to disk?