Board Thread:Support Requests - Getting Technical/@comment-45310000-20200412000750

I feel sorta stupid having to ask this, but what am I not understanding about the Template parser and not getting the expected output:  { {Foo}} -> "" { {Foo|Hello World}} -> "" 

[a link to the template]

MediaWiki 1.33 UCP, if that makes a difference.

(edit: template link added, pre tag used as per Andrewds1021)  