I don’t actually remember but I wonder if it was a fairly empty page with a 505 internal server error. I’ve seen one recently, and can’t think where else it would have been. I’ve seen those in the past on a test site when the database doesn’t reply quickly enough to the web server. Or it can happen if the database gets an invalid query from the web server, but in that situation you’d hope the Patreon add-in you’re using would deal with the error using a friendly message and not throw a 505 wobbler.
There’s a very high chance I’m talking bollocks as usual!!