In T223139#5177918, @matmarex wrote:

This seems to be caused by using non-breaking spaces in the transclusion. For example, in this one from https://zh-classical.wikipedia.org/wiki/廿九棕櫚村:

{{地方
|地方         = 廿九棕櫚村
|地方原文     =Twentynine Palms
|旗號        =
|徽號         = 
|地圖         = File:San Bernardino County California Incorporated and Unincorporated areas Twentynine Palms Highlighted.svg
|歸屬         = [[美國|花旗國]]
|所屬         = 
|屬地         = [[加利福尼亞州]][[聖貝納迪諾縣]]
|治所         = 
|執事         = 
|用語         = [[英語]]
|人口         = 二萬五千卌八
|建置         = 
|省置         = 
}}

Every other space used to align the = signs is a U+00A0 NO-BREAK SPACE rather than a normal space. These spaces are included in the parameter names, and cause the template to not "see" the parameters, and render an empty table.

Replacing them with normal spaces (or removing them) fixes the issue.

This might be the expected behavior?