Known incompatibility with Sonar. Any version of sonar with VST hosting could produce this problem with SOME video cards/drivers and not others. Its a refresh issue confirmed by Cakewalk. This issue is supposedly fixed in a later update to Sonar date TBD.

Sonar can't refresh a GUI and render audio at the same time. ARIA expect the graphic refreshes to be done in a separate core/thread, but its currently not possible.

In the mean time, just close the ARIA UI when you dont need it and glitches should be gone.