Hello,
I submitted bug 56763[1] just now, then realized that this is a part of a larger issue: what is {{#property: }} expected to output.
Theoretically, there could be two extreme answers: raw data as a string, or whatever wikitext which could be rendered as what *readers* love best.
I guess the second answer is the goal, because of ValueFormatter, SnakFormatter::FORMAT_WIKI and $wgContLang->listToText() on final output in our code, but sadly this is never explicitly defined anywhere, including MW.org documentations[2] and development notes[3].