Bub, is it possible you had that track frozen and then re-enabled the CE? The reason I ask, when you freeze track with the PC enabled, it disables PC completely as it is included in the freeze. Or, I've noticed that in some older projects, the master PC light at the top right, was turned off. I'm sitting here working not even noticing the master on/off on the channel was off until nothing I changed made a difference....then I noticed the light was out.
I haven't experienced any of those old anomalies we had in X1 with the on/off thing thankfully. I can say this though...older projects not created in X2 have always been a bit strange for me to where I've had to alter things. I can't remember exactly what I've had to fix, but let's just say that when I had enough of listening extra hard and watching every little thing, I started labeling my songs "name of song X1" or "name of song X2" or "name of song 8.5" so I never make any mistakes. I've found that is's best to always finish a project in the version your started it with just to keep things cool.
One of the things that I DO remember that always happens to me with older projects and X2 is....it always tells me "can't find wave data, so silence will be inserted". Open the project in 8.5 where it was created, it doesn't do that.
As for the CE, I hear absolutely nothing while using the bus CE. The channel CE just gives me a little drive and makes things a little crisper. The only thing I've found this useful on so far has been newer bass guitar tones where a client is crying for a little drive and sometimes on backing vocals to give them a little "zip" so to speak.
The good thing about the CE drive is...it's good drive. One of the best "drive" sounds I've ever heard from a digital plugin to be honest. It's close to a saturation or sorts depending on which model you use. I've tried enabling one on every track like they recommend and then mixing that way. Then, when you turn them off, you're supposed to hear a pretty decent difference. There's a difference, but not one that I personally welcome. I've worked my entire life to keep drive out of my mixes....it's not something I want or need on every track and to be honest, I can't even tell it's being used unless I crank up that gain a considerable amount. I don't WANT gain on my stuff, so I've stopped using these things.
The Waves versions of these are a little cooler as they give you 32 modeled channels to choose from and each channel has it's own distinct sound without using ANY gain at all. So that to me is a little closer to the way this stuff SHOULD be working. But to be honest, I still don't think I need that and definitely don't need it on every track. To be honest....I think some guys just think they like the sound of those things because they look so cool in your project. :)
-Danny