desired behavior is to include the invitation information
Actually, when you forward or reply to a calendar invitation it is intended behaviour to not include the invitation information.
It is common practice to be able to inform or invite other to meetings to which you are not the organizer. I ask that you reconsider the intended behavior to be similar to the intended behavior of other email clients:
OK, I will discuss it with our developers and will let you know if they decide to change it.