I've cross-posted this on the Microsoft Answers site to get more feedback and potentially bring it to Microsoft's attention.
https://www.msofficeforums.com/word/...-sticking.html
Here are screenshots of the EnvelopeAddress style in a document before and after using the Envelope button to insert an envelope in a document. The before settings (blue) were from the normal template which was the basis for the new document; the after settings (red) were after insertion of the envelope.