fader linking intermittent

Hey guys,
Working with Cubase 8 for the first time today. Noticed that the “link channels” option seems to be intermittent.
I was sure to select “volume” checkbox in the link options. sometimes it works, sometimes it doesn’t. Anyone else experience this?

I’m also noticing that holding ALT does not defeat the link for faders. Usually I can hold ALT to adjust a single fader in a group without disrupting the others.