I have an automation rule set up where when an assignee leaves a comment on an issue, the reporter receives an email notification containing the comment using the smart value {{comment.body}} along with a link to the issue using {{issue.url.customer}}.
The problem is certain customers receive the url as a text, not a hyperlink. However this isn't the case for everyone, some people are getting a hyperlink that takes them directly to the issue.
I've attached two screenshots showing how some receive a link and others a plain text based off the same smart value.

