I haven't seen mention of this (but I've been away on and off) but I'm wondering if the X2a bug where a midi track dropped more and more notes while looping has been fixed in X3 ?
 
I'm aware of the turn on the metronome and mute it trick, but I'd like to hear that this is no longer necessary.
 
It would be really nice if there was a fixed bug list somewhere...
 
 

I have yet to experience it in X3 and I just finished looping the same loop for a couple hours. Not sure if that means it was addressed or that other changes simply corrected the issue.  Either way, i hope it's fixed.

There is definitely a bug if you're doing looped MIDI recording with input quantize enabled. I'm a relative newcomer to Sonar and discovered this very quickly.
I made a video showing the problem :
 
http://www.youtube.com/watch?v=MDvryEPNNeE
 
I also submitted a bug report yesterday.
 
 
 

Paul P
It would be really nice if there was a fixed bug list somewhere...

 
The fixed bug list is here: http://www.cakewalk.com/support/kb/reader.aspx/2007013324
It covers fixes in X3, X3a and X3b.