Ha
AFAIU, two platforms other than mastodon (lemmy and discourse) have issues federating because at least one of them is trying federate well with mastodon (for obvious reasons). The mastodon quirk causing issues is, AFAIU, the way it kinda mangles articles and pages (long form formats in ActivityPub), which are appropriate for forums and link-aggregators like lemmy and discourse. So someone hints been done to work well with mastodon’s mangling, which hurts lemmy-discourse interop