Steps to reproduce:

• Search for an Entity using it's mul label or alias via the inline search.
  • e.g. https://test.wikidata.org/w/api.php?action=wbsearchentities&search=John+Doe+II&language=en

What happens?

• The inline search itself is unable to find all mul labels or aliases (Update: This used not to find any matches "No match was found.", now it finds the alias "John Doe III" of Q225561 that I created on test, but e.g. still not the Label "John Doe II" of Q57591.)

What should have happened instead?
The inline search should find Entities by searching for their mul label or alias (just like other language code).

Notes:

• The same search works just fine using the advanced search:
  • https://test.wikidata.org/w/index.php?search=John+Doe+II&search=John+Doe+II&title=Special%3ASearch&go=Go&ns0=1&ns120=1

• This behavior can also be reproduced within entity lookup fields, for example, when adding a statement value

Acceptance criteria:

• We understand the problem that leads to this issue.
  • The wikis using the mul language field must be reindexed
• The problem is solved (or if solving the problem is out of scope, then please create a follow-up task, so we can discuss it).