no Federation with instances that use altered versions or proprietary versions of AP.
It's especially funny given (the last time I checked) neither kbin nor lemmy actually followed the spec properly. They ignore the jsonld requirements and resort to field names, that, by the spec, should be dropped.
Edit: lemmy is actually good now!
But lemmy doesn’t use “plain json”, it annotates some fields with the schema, just not all of them, which makes it a mess. You either do json-ld proper, or you don’t do it at all.