A weird glitch that appears just related to one project. Not to mention some subtle pops/ scratch on playback (Acoustic guitar and vocal, with a midi drum track ) , speed changes!!! One time I opened it, playback was too fast / higher pitch. This morning, slow and low! I have tweaked some with ASIO settings, but why would other projects work fine?!  In use... Sonar Professional,  Scarllet 8i6, Windows 10.
 
 

The only thing I can think of is the clock or effected tempo got wacky during your original recording / tracking. You can try DPC latency tests to see if there are interruptions on the buss. This could explain random drop outs, clocking issues, pops clicks etc. IF all your other projects are fine then maybe it was an issue while tracking and monitoring an instrument VSTI during the original recording.

Thanks....since this post ( I did another post under the Computer section), my computer / Windows 10 forced a reset , complete reinstall on me!!! So I never even got to try any troubleshoot, and now have to completely re install Sonar! So maybe his will fix itself??!!. Maybe that glitch was a cyber- message / omen. Lol. I will follow up.