Same here. I opened a support case and got a response: I have verified with development and this seems to be by design not to show pieces of information to existing WHD client cc recipients. As it is the design, I can however submit a feature request asking that they consider adding that information to those recipients.
If you try to cc an email address that is NOT already a WHD client on your system, the custom template works fine for the cc person. I think it's a bug but they call it a feature.
Thanks for the confirmation.
@solarwinds - I could understand when certain pieces of information from the ticket itself should be restricted for any CC recipients, but we are talking about general information that should exist in any E-Mail regardless of who the recipient is. The template defines for example our own company logo, a welcoming message describing in plain language what the ticket is all about (creation, update, etc.) and the company signature (which is required). The CC recipients get instead just an E-Mail containing the ticket contents.