which only appears after first inputting the username, I’ve just been using old devices to access the site before I noticed this on a laptop yesterday.
I don’t run Patreon-anything or Discourse-anything, but if you’ll allow me to make some assumptions I reckon there is somewhere in Discourse where (maybe) you have a plug-in of some sort that hopefully specifies what the Redirect URI should be and there’s somewhere on Patreon where the same URI is supposed to be set. I suspect these two are set to different values?