Yes , I have had that happen to me only one time in a project and it drove me nut's ..
I had no idea what was going on , I shut off all the pro channels and re engaged them . the bass track w the concrete limiter wouldn't re engage the concrete limiter…the blue button was on …nothing was coming through and the C L showed no acticvity
I wound up closing the project down w out saving and loosing a few edits I was happy with …
usually I always do a manual save every couple of effective edits…
this time I bit the bullet and cut my losses …to this day I still don't know what happened ….
when I reopened the project the concrete limiter on my bass track was working again ...
it only happened that one time , all though I didn't mention it at the time it was contributing factor as to why I started that I can't trust my DAW thread ...
oh , edited for system specs...
Asus Lap top , intel I3 , OS Win 8 64 bit , 6 gigs of ram , 2i4 usb sound card, X3 e Pro 64 bit install .
Kenny