After user update automation: can it trigger from one required field, while optionally including other profile/custom fields if present?

OK, turns out that it doesn’t.

And keeping the parens in breaks the automation. Got this in the logs:

Mustache::Parser::SyntaxError (Unclosed tag
  Line 12
    * guidelines: {{community_guidelines_(understood)}}
                                        ^
)

So, do I need to submit a bug/feature request to have symbols be stripped from field names?