Video player stuck in "Seeking" state, with Seek OSD visible

Hi,

after a series of system updates which I unfortunately can't unwind, one of my XBMC installations is now exhibiting weird behavior: For every video stream I try, the video player appears to be stuck in "Seeking" mode, with the Seek OSD remaining visible. Except for this odditiy, playback appears to commence normally, progress is shown properly in the info OSD etc. The effect happens with all formats I've tried (AVC MKVs, MPEG2 VOBs and XVID AVIs).

Debug log from sample run: http://paste.ubuntu.com/5688536/
Platform is Ubuntu 12.04.2 LTS, i386, Kernel 3.5.0-30-generic
Hardware: Gigabyte P35-DS3, C2D E6750, 2GB of RAM, Nvidia GT 610 (GF119)
Output device is a Denon AVR 4311 connected via HDMI
Nvidia driver is 313.30 (also tried 313.26)
Tried XBMC 12.2 Git:32b1a5e (installed from stable PPA) and 13.0alpha (installed from unstable PPA)

The system worked fine until some recent package updates. Since I didn't immediately notice the problem, information on which packages were updated was lost, though. I have several more XBMC installations on various hardware (Intel i3 IGPs and IONs) which don't exhibit this behavior, even with the same media files.

Any hint is appreciated. Thanks!

Best Regards,
Olli