Hi @mjl-,
I am happy user of mox for some time, but today I saw something that seems like a bug.
I recieved email from my wife from her work address, and in webmail (I don't use any other client) I see no From header.

But when I open email source, I see encoded From header.

Maybe there is a bug in parsing? Maybe the new line in between is not standard?
It was sent by Exchange 365 server from Outlook in Windows.
I can privately share you the source email, it was just a request for print of some application document.