Hey there
I had issues with Paste for a while, usually I would thing, "Wondering where it pasted it"- thinking it went on some wrong track which was accidentally selected. At first, I was noticing that I would press Paste, and there would be no clip. Try it over and over, and it would not happen. If I close Sonar and reopen, it would work for few clips. I assumed- "oh, well, something went wrong, but it working now- not big deal".
Last night it was acting out really badly. I was at the beginning of new project- no time to have errors- may be X2 8 measure tracks- MIDI and Audio. So I am trying to Copy/Paste this MIDI clip, and instead of going in measure #9 on the track 2, it creates new track and pastes in measure 14. Just simple Paste, not even special. After trying several times I gave up, restarted Sonar. So it pasted in the right place after restart. 
But I wanted to paste 8 measures 20 times. So I went in to Paste special, set it to X20, I believe I had the top box in middle column checked in Advanced- is it alight to measure? (where it would show 17:00:12 or any location if it unchecked but gets grayed out when checked). So it did Paste X20 clips.
So I am on the next track, and I want to do the same- copy and Paste X20, but this time it pastes in to Measure #9 correctly but after that- every clip starts one measure farther- has 1 measure hole. So if the next supposed to go in #17, it went to 18. Note that I am using Paste now, not Paste Special but it still pastes X20 times, when it supposed to Paste just one clip. So I am going to Paste Special settings and set it to Paste X1, but it continues to paste X20 clips. So I close Sonar and reopen. It Pastes X1. I am thinking, "Ok, it working now". Select X20, and it starts pasting with hole again (one empty measure between the pasted clips). Any suggestions? Thank you. 
 

May be related to having ripple edit on… 

Thank you for your reply. What is ripple edit for and how do I turn it off? Thank you. 

https://www.cakewalk.com/Documentation?product=SONAR&language=3&help=Arranging.22.html
 
More info about it in this kb article and check out the Tech+Music issue referenced in the article.
 

There has been some heavy copy paste errors baked in as of recent.  Ive read of them and experienced many myself.  Ripple edit - is a new feature that can be very very helpful - however I think it still has some bugs with certain systems.  In splat - go to the track view (not console) - which it sounds like you are already on - and at the top left of the track view itself choose "options" - and ripple edit is there.
 
Im not convinced that is the issue however - and think this is  a bug.  I had a session last week that seemed to go absolutely crazy no matter what I did....  including copy paste errors.   At one point I would go to copy past a gang vocal part of 8 tracks - and the paste special dialog would not uncheck the "paste to one track" dialog without a system reboot.  There were tons of other errors however