group track mute problem

we have a problem with cubase 6 on a pc

when pressing the mute button on a group it mutes the signal ok , and the button lights up

but when its pressed to unmute , the light goes off as if unmuted , but theres no audio
the only way we have found to get the audio signal back is to then draw in some mute automation on the effected track and then it will work again

we can replicate this every time

-set up group with audio track / instrument going thru it
-press mute on a group

  • press un mute on group
    -result light goes off , but no audio thru group

-work around - draw in mute automation to get signal back

any body else seen this ??.. thanks

specs are
cubase 6.02
win 7 pro 64 (running c base in 32bit )
intel 17 970
gigabyte GA-X58A-UD3R
6 gig ram

Is it un-muting the tracks that are routed to it?

yeah the mute lights are off on all the associated tracks through the group
it seems so be an intermittent fault as some times its fine but then it all goes off an you have to draw in automation to make it come back

Have seen this too. But not every time and maybe it was only 6.00 and 6.01. I’m not in the studio right now so I can’t look into now.