Steps to reproduce the problem.
1)Load some sine wav
2)F7 → process → pitch shift
3)Uncheck “Time correction”
4)Switch to envelop tab
5)Hit “reset” to reset envelope
6)Tranpose:0 Fine Tune: 0
8)Process → Add another pitch shift instance
Then add another one and another one.
As many as you would add you might hear the artefact static noise increasing, but it is apparent with only one layer.
You may use an analyser to this, it’s happening on the high frequencies.
This happening for me on all of my cubase versions, 10, 11, 11.02, MacOS, Catalina.
And also at my friends Studio, Cubase 10.5, Pc, Windows 10.
Would appreciate if someone can confirm this is happening at your end also, although this comes and goes… but mostly apparent.