I see this has now been marked as a duplicate bug:

https://bugs.maemo.org/show_bug.cgi?id=9009

(Please vote for this new bug)

However nothing really seems to be happening and the devs seem to be ignoring the problem possibly because it is not always easy to replicate. I have since abandoned the in-built Media Player and use kmplayer for internet streaming myself, but this is not really the point, the software Nokia shipped with the phone pre-PR1.2 worked fine, it now doesn't, they should fix it and I should not have to install third party apps to get a basic function of the phone to work again.