This problem has been going on forever, Adobe has known about it for well over a year, and still no solution.
After the latest update, I have created a brand new sequence, and the bug persists. It is thus false advertising for Adobe to even claim that Premiere has any multi-cam functionality, because this massive product bug renders the function completely useless. We all need to change angles while reviewing footage, obviously.
Adobe will either fix this, or will not. After a year, I'm shocked that they've let this go.