I was giving out portals to the End of Time. They were thanking me. To be courteous to them my typical response was “'Welcome.” I could say that in party chat as well as private messages.
At one point I was trying to send one such courtesy response to someone who had just thanked me for a portal and I received the response:
Your message has been detected as containing content which does not adhere to our Code of Conduct and has not been sent to chat.
I received the above message a few times as well as another short error which I did not capture and another message when I tried to send a longer message to global chat including the text “'Welcome”.
This happened about 5 - 10 minutes ago.
I think it goes without saying that a courteous message such as this should not violate a Code of Conduct.