Wrong email template being picked

I understand that the Invite Mailer template should be automatically picked up if the CSV contains a valid topic_id. For me, this is not happening. The template that is being utilized in Bulk Invites is the Invite Forum Mailer.

The spanner in the works here is that I want to use interpolations related to topics e.g. topic_title etc. and the Invite Forum Mailer does not allow that, but whatever I read tells me that it should be the Invite Mailer template that should be picked up anyway.

How can I troubleshoot this or workaround this please?