I would suggest you to contact the amazing Coda Support and report this through Intercom (by clicking on the big question mark ? which should be sitting at the bottom right of your screen when you’re in a doc, then selecting Get support in the menu and finally clicking on Send us a message )
I honestly can’t remember how this was working before, as it has been quite a long time since I’ve used HyperlinkCard() (I prefer embeds ) but I don’t think I ever needed to Concatenate() the card before …