Issue: disambiguation page issues

On my XF 1.x test board, I have attempted the following:

1. On a page that needs disambiguating, click Options > Disambiguate this page.
2. On the form, click "+New disambiguation page"
3. Enter a title and create. (This completed successfully, and the disambiguation form was updated accordingly).
4. For the disambiguation form, enter the appropriate descriptions.
5. Click Save.

On #5 I did encounter problems, but you reported that you encountered problems on #3 (the resulting disambiguation page being inaccessible). On my board, I can visit the disambiguation page just fine, but problems at #5 prevent me from adding entries to it.

Please clarify your issue.

The description of your problem (a new page that routes to the wiki index instead) sounds a lot like this:
https://www.vaultwiki.org/issues/6168/
which was fixed in a subsequent patch, and from the comments it seemed like you applied the fix. But as you are still having similar issues, please verify that your code is patched already by following my instructions in that thread.