Lumetri color is vastly improved over previous Premiere Pro versions. But, the auto color is not working on the timeline clip. Auto color does work on the source clip. I think it worked on both clips in beta 22.2.
I used to color the source clip, but it turned out to be too much of a pain in the ass, because everytime I played it to get the scopes to update it would revert back to the timeline clip and then I had to remember to go back to the source to make the adjustments. So, I just started color editing the timeline clip and copying the lumetri settings to apply to other similir clips. I know I could use adjustment layers but I'm not working on clips with the same constant lighting like you find on a movie set. So each clip usually gets minor adjustments to lumetri settings as I go along.