Recruiting Content Library - "Candidate Pool Job Notification" doesn't support html formatting

With the Recruiting Content Library category "Candidate Pool Job Notification" I encountered that our standard notification formatting is not supported in this category (see screenshot):

Although I use the exact same formatting in all other Recruiting Content Library notifications, even the ORA ones (e.g. Marketplace Opportunity Notification).
I have copied the exact same html code into the Candidate Pool Job Notification but it doesn't work. I really don't understand why it doesn't work for this notification category but for all the others.

Is this a bug?