@AltCode I forked this out to a new topic. I think it's time to loop @pfefferle@mastodon.social into the conversation (at the very least so this could be potentially escalated).

Mattias, it seems that when the WPML and ActivityPub plugins are enabled together, notes federated out by the blog user in another language have different ids but the same preferredUsername.

e.g. ruari@vivaldi.com: https://vivaldi.com/?author=46 and https://vivaldi.com/ja/?author=46

NodeBB interprets this as two different users. Curiously, Mastodon does not, the second ID explicitly does not resolve.

So there can be two solutions here:

1. The underlying issue can be fixed by WordPress, the solution of which is out of scope (for me at least)
2. NodeBB can adopt whatever mechanism Mastodon is using... which is most likely that Mastodon does a two-way when asserting an ID, and ensures that the webfinger resource points to the ID.