[SOLVED] Some songs will not remain set as clock radio

[FizzyTea]

I have an issue where certain tracks will not remain set as clock radio.


I set the problematic track as clock radio through the UI.
The info box pops up and says "clock radio updated"
The moode.log shows  "worker updclockradio"
If I check the clk panel immediately the setting appears to be updated properly.
Within a few minutes however or after a reboot the clock radio panel has reverted to the previous set track.

I know this would be difficult to reproduce.
What logs can I look at to try and identify the problem?
I have had a look at the id3 tags but cant see anything strange. 
I have taken a problematic track and removed id3v1 tags leaving only v2 tags but this had no effect.
I wonder has anybody else had this problem?
Does anybody have any advice on how to proceed with troubleshooting this issue?

How does the clock radio work? Is there a script or section of code I can inspect?

Thanks.