Noisy stereo bus in x2a.

I'm mixing a 24 track song recorded on a dedicated hard disk recorder, digital piano recorded to analog wave files. No MIDI content. I'm getting intermittant noise on the stereo bus for the piano that sounds like a latency issue regardless of the buffer settings. I save and close, restart.....everything's fine for a few minutes, then the crunch comes back. I've frozen several tracks, makes no difference in the behavior. Interface is RME and drivers are current. Anyone else experienced this bug? My DAW is more than robust, it's not a horsepower issue. It's only on this particular bus and it's a piano driven song, driving me freaking nuts!  

No clipping anywhere, gain staging is correct, end of fx chain bus level tops out at -6dbFS on loudest part of performance. Average levels of actual tracks are -15dbFS. All fx are via the Pro Channel: Compressor, Console Emulator. I forgot to mention that if I try to engage the EQ on Pro Channel, Sonar tells me I have Sonitus EQ on that track and cannot engage the PC EQ. Funny, I can't find the Sonitus plugin in the fx bin. I'm beginning to suspect a corrupt .cwp file.

river
I'm getting intermittant noise on the stereo bus for the piano that sounds like a latency issue regardless of the buffer settings. I save and close, restart.....everything's fine for a few minutes, then the crunch comes back. 

I've experience something like that - and it turned out that a dry signal through a reverb on a bus cause it.
Saw to that reverb was all wet - and it went away.
so something to do with direct signal going two ways - and as you said latency thing it seemed.
 
Really weird thing, the crunch noises came exactly when L2 limiter reached threshold. For me it was breathing noises of vocalist so I started to edit them away, before I found the reason.

I've isolated it to the Pro Channel module on the bus I'm using for the piano. It's not clipping because if I disengage and then re engage the module, it goes away, then comes back after a few minutes and making several changes to the mix and stopping/starting playback. I've also inserted a plugin for identifying intersample overs on a track or bus, not even close to going over zero. Crunch was a bad metaphor on my part, it's crackle.

For future reference, see the "Loading legacy projects" section near the bottom of http://www.cakewalk.com/D...Channel.2.html#1211774

Hi. Did you Ctrl left click on the on / off button on the Pro Channel EQ?
Best of luck.

That is very strange. Someone here (with much more knowledge than me) will hopefully figure this out for you.  
Anyway, best of luck.
 

Glad it worked out for you