Oh, sorry, I missed that this was specific to the landing pages plugin. I’ve moved these replies here so our friends at Pavilion who developed this plugin can look at it when they get a chance.
It’s not unusual for plugins to need a fix to remain compatible with the latest version of Discourse.
@PCPal thanks for being proactive and posting an issue on github. I think it’s fine to talk here, or you can report a bug to pavilion using their form (see first post for the link).