Issue with muting folders in Cubase 6

I’m not sure if I’m posting this in the right place, but am having an issue in Cubase 6.5.0

If I have a folder channel, and accidentally mute it in the arrange window, when I undo it, it doesn’t go back to the previous state, but just unmutes all audio/midi in that folder, even if it was muted before.

This means I have to go back to a previous save version and get a print screen to then reference what the state of all clips in that folder was.

Any ideas if this is a known issue or if I’ve missed a specific update?