I'm slowly migrating to 7.5 but have increasingly noticed some weirdness with mute states.
The keyboard shortcut 'm' for mute occasionally stops working in the arrange window. However, it continues to work as expected when MC has focus. It may work for some tracks, but not others.
I've also found that sometimes, when muting a group, all the tracks routed to that group remain muted even when the group has been unmuted. The only way to clear this is to manually unmute each track, one by one.
Another issue which has crept up a few times is that MIDI sometimes fails to play back on an instrument track, even though I can play 'live' from my MIDI keyboard on that track. MIDI parts dragged from other tracks are also ignored once this behaviour starts to exhibit itself on a project.
I've never experienced these 'bugs' in previous versions, and it doesn't happen on every project, but it's very annoying once it does and I lose confidence in Cubase7.5, which I've only recently decided to use for any serious work.
Anyone else having similar issues?