I created a play list using MusicIP, if I remember correctly about 50 tracks. At some point the now playing view on the controller freezes on a certain track. The album art freeze as well as the information and the time remaining becomes a negative value. If I try and view the play list, the controller just shows the 3 wheels (hourglass) and never gets the list.
 
The Squeezeserver continues playing the list correctly but its not possible to see which tracks playing on the controller.  I can stop, pause and resstart the current(correct)track. If I reset the control then the "now playing" track is correct (in sync), but its not possible to get the orginal play list. 
I'm using the beta release and the same problem occurred on the last two updates 

SqueezeCenter-7.1-21511
SqueezeCenter-7.1-21761

It seems consistance in that it occurred every time I've create and MusicIP playlist