First @... you are a rockstar for this. You deserve a taco 🌮! I use several conditional fields and it makes for an ugly output end user side if they are not hidden.

Second to echo the two seperate comments above:
@... Ram is correct, the original example code given does have spaces that need be removed for the closing {{/is}} and {{/each}} tag.

@... the reason the normal hyphen did not work when you typed it vs copy is because it is actually an em-dash. Which is basically a fancy way of extending the normal hyphen length. The em-dash can be entered vs needing to copy/paste it. For Windows you can insert one of the following ways (I do not Mac so I do not know those instructions, but I am sure it can be found on Google if needed):

1. Press Ctrl + Alt + minus key (-) on number pad (doesn't work on a laptop).

2. Use the windows alt code (not convenient).

3. Press the Windows key (⊞) + period (.), select Ω and scroll to select the em-dash — to the right of the regular hyphen. (This is the easiest to remember if you use both a desktop and laptop).

Replacing the original custom fields code with the below in the request_page.hbs template, worked as expected and hides the custom fields with a blank value. Make sure you are not accidently editing the requests_page.hbs template.

{{#each custom_fields}}
{{#is value "—"}}
{{else}}
<dt>{{title}}</dt>
<dd>
  <span>{{value}}</span>
</dd>
{{/is}}
{{/each}}

Hope this clarified a few things for those with questions, but this works great!