Consider this test case demo'd at semantic mediawiki sandbox.

Pages Saale, and Saale2 do not exist.  Unlike Saale2, Saale is referenced by page [[Halle (Saale)]] within  [[Property:Adjacent to]]

"{{#show:Saale2| default=expected behavior. | ?Located in= }}"  results in -> "expected behavior."

"{{#show:Saale| default=expected behavior. | ?Located in= }}"  results in -> ""

Bug, no?

-Phlox