“Sorry. Aborted Patreon login for security because security cookies don’t match.”

This is specific to hosted WordPress sites at WPEngine but may help others. If you are getting this error go to WPEngine support which is hands-down the best on the Internet for WordPress (or your current host) and ask them to exclude the “patreon_nonce” cookie from the cache. They need the exact spelling of the cookie.

This resolved it for us.