Render in Place color weirdness

I'm trying to do a render in place of a color corrected clip. I don't have DR color managed on. When I render in place, the rendered clip's color changes drastically. It's almost as though the color grade was applied a second time. So if I bump contrast up 15, it'll bump up another 15 when I do the render in place. Is this a known bug?

Disable the nodes, as they will be applying the grade to a clip which already has it baked in.

They are automatically disabled here in 18.5b3, and reactivated after a ‘Decompose in place’, as it should be.
Please note that I’m on a Mac. If that doesn’t work as expected under Windows, you should post the bug in the beta subforum, since you are using 18.5 too.