I have this simple wikitext that used to work:
{{int:foo-{{{1}}}}}
In 1.29 this no longer works, and always produces:
Special:ExpandTemplates output:
{{int:foo-{[[:Template:1]]
Special:ExpandTemplates XML output:
<root>{{int:foo-{<template><title>1</title></template></root>
Special:ExpandTemplates HTML output:
<p>{{int:foo-{<a href="/w/i.php?title=Template:1&action=edit&redlink=1" class="new" title="Template:1 (page does not exist)">Template:1</a></p>
If I place that in a template and provide a value, result is the same except for XML output:
<root><template><title>Langname</title><part><name index="1"/><value>fin</value></part></template></root>
In 1.27alpha [1] I still get expected output:
<root><template><title>int:foo-<tplarg><title>1</title></tplarg></title></template></root>
<foo-{{{1}}}>
[1] https://sanat.csc.fi/wiki/Toiminnot:Mallineiden_laajennus