Sorry to necro this but I’ve been on hiatus personally. 2020 has been a mess all around and I didn’t have place for WoW since late March till about a week ago.
But this issue remains, at least on Mojave. I did play on a separate Catalina machine for a little while but I no longer have that machine. I can’t say I ever saw this issue on Catalina. I wish I had more data points other than my own here.
My 2019 MBP is still sitting on 10.14.6 and likely will skip Catalina altogether due to logistics around my non-gaming usage of this system (e.g. work) and the fact that Catalina is generally considered a hot mess of an OS release.
To your point about there not being a ton of reports about this, bear in mind it is one of those subtle things only the folks cursed with OCD might get tweaked hard about. This issue doesn’t surface in normal gameplay when the player is actively doing things. It’s during no-input times like auto-running or flying on FP. I suspect most people don’t notice it or don’t care about it. ¯(ツ)/¯
Very possible, it’s just difficult for us to find reproduction steps with so few people reporting the problem. The thread’s mostly dead other than your contributions. At this time we’re working from home so I don’t even have access to the mac we typically test things on in CS. If you’re still convinced of a bug it’d be worth bringing up in #support:bug-report. Beyond that though, you might try setting up a dual boot to see if it still happens on that PC on a different supported build of mac OS (Catalina, High Sierra, etc.) That said you’d also probably have to configure your other OS with many of the programs you use on your main OS just to ensure that you’ve got as close to the same setup as possible.