How are some posts getting past [reverse] defederation? - eviltoast

https://lemmy.world/c/technology@beehaw.org stopped receiving new posts about two weeks ago when they defederated us.

Except today we got this new one, and some folks on this instance have been commenting. We can’t see their comments, and they can’t see ours. How did the first lemmy.world user see this post in order to make a comment on it here?

PS: Do we have a better term for the situation where another instance has defederated you, distinct from when you’ve defederated them?