Does anyone else have an issue with their N900 where the FM transmitter turns itself off after about a minute of silence?

If I switch the fm transmitter off and then dont play any sounds I find after aproximatly a minute the FM transmitter magically turns itself off. This is a real pain when I use the GPS software since there are often long pauses between voice prompts.

If I use the media player to play music then the transmitter stays on, it just seems like if it is not used for long enough then it simply switches itself off. Having to alunch the media player every time I want to use the gps is a bit of a pain!