Bypassing FX pressing E.

Ok so the other evening after I updated I was in a project and when I'm mixing I like to turn off the fx globally from time to time by pressing E, (just to see where I'm going), Anyway I pressed E and the fx bypassed immediately without the audio stopping, this had never been the case before, usually there would be a stop while switching, I thought 'Fantastic' this is something I wanted, But unfortunately I went out to the studio today, Opened up the same project and while working pressed E to bypass the fx and the stop is back. I really can't understand this, It's the same project, same amount of plugins and the first time I was back in platinum since the other evening. Anyone got any ideas what might be happening here.
Thanks Guys.