My survival world never had the C&C Toggle during the 1.17 betas, and never had Vanilla Experiments (or any other experiments) prior to updating to the current beta. However, when I updated to 1.18.0.27, my survival world (as well as the backups [copies]) had the "Experimental" on the world detail on the World screen. I checked and none of the Experimental toggles were turned on, and I am more than a thousand percent sure that I have never turned on any experimental toggle on my survival world.