macOS Catalina 10.15.2
EDIT :
Screenshot post #1 was from REAPER v6.01/64 rev f80638
I didn't use REAPER notarized for Catalina because when building VST3 using XCode 11.3, REAPER can't be attached for debugging.
Here is screenshot with REAPER v6.01+dev1212 from LoL
A bit different, but still doesn't look consistent compared to arrange.