Have a template like so:

[[Category:Foo {{{1|bar}}}]]

Use it in a page like so:

{{Categories|Bob}}

Output from Parsoid:

<link rel="mw:WikiLink/Category" href="./Category:Foo_Bob#Category:Foo%20Bob" data-parsoid="{&quot;tsr&quot;:[0,18],&quot;src&quot;:&quot;{{Categories|Bob}}&quot;,&quot;dsr&quot;:[0,18,null,null]}" about="#mwt1" typeof="mw:Object/Template">
<meta about="#mwt1" property="mw:TemplateParams" content="[{&quot;id&quot;:&quot;mwt1&quot;,&quot;target&quot;:&quot;Template:Categories&quot;,&quot;params&quot;:{&quot;1&quot;:&quot;Bob&quot;}}]">

Note the wrongly-set category sort key of "Category:Foo%20Bob" - should instead be blank.

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Severity: normal