Normally you don't need to disable VaultWiki on your own because the upgrade script does this. However, once plugins are re-imported we can have conflicts again.
We always test the upgrade script on our sites before making the ZIP available. We were happy to see this time that there were no immediate issues, but it appears that afterwards, when the ZIP was formed, that the correct version of the plugins file was not included.
You can complete the upgrade by disabling VaultWiki, downloading the ZIP again, replacing: vault/install/ces_nwsp_spec-plugins.xml
And navigating to: /vault/install/finalupgrade.php