user not informed about new chat

[GraemeMcCarthy]

Teams App; Windows 10.

New Chat with internal user -- they get a notification (popup).  If they don't see this and click on it then they have no knowledge that the conversation is happening/activated: nothing in their Recent nor Chat tabs.

[#2]

They most likely had the chat open in the background on the chat window that came in. That's the only time I've seen this happen.

Are you sure the banner notification isn't a Team chat via a Team? This will not show in chat if that's the case.