In Minecraft's 1.21.30, there seems to be a bug that the chat is not displayed on the friend's screen even if you send a chat to a friend on Nintendo Switch.

※This bug may have existed since the previous version, but it is reported in the latest version.

[Description]

It seems that there is a bug that the chat is not displayed mainly for Nintendo Switch users who are not signed in to their Microsoft account. It has been confirmed that all users who are usually signed in are displayed in the chat. Mainly, all cross-platform users are displayed to each other. The language setting is set in Japanese.

I'm sorry for my poor explanation.😔 That's all for the explanation. Please let me know if you want to know more information.