Sonar 8.5 audio dropouts and popping

Hi
I am having a problem that others have had over the years. it has been posted around the net over the years. With mixed solutions. None of which are working for me.
 
Anyway. I have been working in the same project for a few years. And yesterday, I began noticing that when I split clips in order to process the isolated clip, it creates a pop during playback when crossing over splits. More specifically, I have been using the old Cakewalk pitch shifter to correct certain parts of vocals. I usually have no problem. Later the same day, the pops got progressively worse and finally I am experiencing major dropouts. Cannot even play a half second of audio. Even if the marker is set on empty space. It will not play.
 
I opened other projects which have far more tracks and real time effects. They play fine. So the problem is embedded within this project. I tried saving as a CWB file. Then reopening into a different location. No change.
 
Here's the kicker. I opened a big project that works fine. Then copied and pasted all the audio from the problem project in it. Suddenly the good project would not play. Dropouts. Then I did an UNDO to remove the pasted files. Suddenly the good project worked again. So the problem exists right on the timeline.
 
Something else to note. Cakewalk has had a long history of creating extra garbage on the timeline when using their old plugins. You can right click clip, then process it through the pitch shifter. Click OK. Then it aside from processing the clip, it creates garbage on the timeline that you have to manually delete. And often, you cannot see the garbage unless you zoom way in and examine the timeline.
 
I have read that others have been having the same issue with X3. And to reiterate. No other projects are affected unless I copy and paste the problem files over to them. Anyone have any ideas how to figure out whats causing this??

Thanks very much for the reply. I just happened to find the problem. And I think your solution of bouncing the tracks would have fixed it. As it turns out, I have realtime FX bins setting on individual clips. And every time I split one of those clips, it creates new instances of those FX across both clips. Resulting in more CPU usage. What started as two FX instances ended up as over 8! I deleted the bins and the problem went away.
 
So its a minor annoyance. Splitting clips also seems to create new nodes on the envelopes, which I don't like either. I do wish I knew of a way to stop this behavior. Thanks!!