https://bugzilla.kernel.org/show_bug.cgi?id=198713
--- Comment #3 from Jon (jon@moozaad.co.uk) --- (In reply to Mike Lothian from comment #2)
As a workaround try amdgpu.dc=0
Well spotted. Workaround has stopped the traces as you'd expect. It's also stopped the weird blue flicker I was getting in KDE with OGL3 compositor (different DC bug).
I hope the above is useful for getting PRE_VEGA out of experimental!
Missing from original report, it's 3x BenQ XL2730Z, all display port.