. . . so bizarre, never heard of this one, your computer specs seem top notch, but I'm thinking graphics card, running out of memory ?
Also, you have waded into the murky waters of Win 8.1, cutting edge, but I wonder . . .
I'll be interested to see if anyone else has seen this at all.
If you restart Sonar, does it fix it ? Or, do you have to reboot Windows to fix it ?
Or, only reloading the track icons fixes it ?