There’s currently a very aggressive camera turning/snapping bug, some describe it as “sensitivity going crazy” for a moment and causing their camera to jerk/change into a random direction.
It’s a pretty nasty bug because there’s a large amount of troubleshooting, as an immediate go-to, that can temporarily reduce the issue (such as lowering DPI/sensitivity) but does not solve the issue. The list continues, and the majority never work for anyone besides some odd case where someone “thought” their issue was fixed.
I figure there’s probably way more on their plate atm to deal with, but wanted to mention it for completeness. On BFA this mouse issue did eventually get fully resolved with a patch, and at least for a time has not returned (span of time I noticed where there weren’t any reports of it, have not checked in a long time). There were cases of this much farther in the past as well, off and on.
I also wanted to mention this incase someone gets caught up in the troubleshooting spiderweb so that you know it isn’t you and that you just need to wait for it to get resolved.
put this command into your chat:
/script SetCVar(“rawMouseEnable”, 1);
That’s what solved it for me.
Although that has been successful in the past, the raw mouse command has very recently caused an issue with cursor sliding on BFA/retail (might not anymore, might not with classic, will test), and does not solve it for everyone. I definitely implore them to look into this issue after Classic has calmed down, ideally before anyone unsubs over it as a number of posters did with the previous hiccup.
I am also having this issue, I do not have it going on in retail I am trying the poll rate change to see if this gets fixed. It is happening to a friend of mine as well so it has to be a software issue.
If you have Razer Synapse software check that the Razer “Stats” software is not enabled. Open Synapse - along top bar is “Stats”. Open that - if enabled - disable “Data Tracking” in the Stat’s settings.
Also graphically in RFK/RFD and some other spots, when the camera auto adjusts for increasing room size all textures may disappear.
This happened to me when I enabled a maximum framerate lock. May not be 100% related, but the issue seemed to go away right after I reverted the change. 
This has been going on since Vanilla and every xpac I’ve played.
It’s never been fixed. It’s not sensitivity, merely clicking will whip the camera around. I’d be auto running and right click and before I even turn BLAM I’m off in another direction.
Saw the same thing in Vanilla beta.
It’s never getting fixed. Annoys the heck out of me.