Already on 15.1 but still “failed sanity check” when trying to do root patching.

Hello, I’ve already updated my 2013 Mac Pro to Sequoia 15.1 (via the update button I’m afraid, not with a bootable USB drive), updated OCLP to 2.1, but I am unable to apply root patches, I keep getting the “failed sanity check, unable to continue patching” error. I couldn’t follow Mr. Mackintosh’s excellent instructions on this subject because there are no MacOS updates to apply (I’m already on 15.1), and thus to interrupt in order correct the problem. Any help will be very much appreciated!