If at first you don't succeed, issue another update. That's exactly what Apple did today when it reissued iOS 17.6.1 slightly more than a week and a half after it dropped the update the first time. The original update carried the build number of 21G93 and the new one released today has a build number of 21G101. The new version of iOS 17.6.1 fixes a bug that could prevent users from enabling or disabling the Advanced Data Protection feature.