Your continued issue is probably due to corrupt pages which are covering your index with a corrupt book.
This seems to be the case according to your /wiki/Special:AllPages page, which should not have any blank lines.
To correct this issue, there are a number of tools in the admin panel you can try:
- Wiki > Maintenance > Rebuild Counters / Caches > Remove Corrupt Content
- Wiki > Maintenance > URL Conflicts. Find the blank entry in the conflict list, and edit the conflict. Once all conflicts are gone, I don't think you should have a problem.