User blog comment:Rappy 4187/Technical Update: November 2, 2016/@comment-24473195-20161103171231/@comment-24473195-20161104073304

I'm guessing that your browser or some other tool is somehow  transforming those requests, considering that staff confirmed that issue.

Here are some simpler test cases using curl:

curl -sSf "http://dev.wikia.com/wiki/Special:Search?search=+"

curl -sSf "http://dev.wikia.com/wiki/Special:Search?search=template:"

Heck, despite using somewhat different search engines even wikipedia has this same issue, see (https://phabricator.wikimedia.org/T149416):

https://en.wikipedia.org/?search=%E3%80%80

This may be fixed next week on their side though, so that url may eventually not show anything.