I’m pretty sure that neither the Primary Name fact nor anything attached to it ever makes its way to Ancestry via TreeShare. I’m not 100% sure it would work, but I strongly suspect sure your m4a file would have made it to Ancestry just fine if instead of to the Primary Name fact you had linked the file to the Person record or to a Fact such as Birth or Death. it’s obviously pretty illogical to attach evidence of a name to a Birth or Death fact. I just use them as examples. But it does make sense to attach an m4a file to the Person record if the m4a file is evidence of a name.
The reason I say that is that the Primary Name fact does not make it to Ancestry via TreeShare is that RM does virtually nothing with the Primary Name fact. For example, the name that makes its way to narrative reports in RM is not the name from the Primary Name fact. Rather, it’s the name from the Person record. And no media or citations or notes from the Primary Name fact ever make their way into any of RM’s narrative reports.
The only purpose for the Primary Name fact in RM seems to be to serve as a way to swap out an Alternate Name fact with the Primary Name fact. Because the Alternate Name fact supports media and citations and notes, the Primary Name fact also needs to support the same items in order for the swapping to occur. But the name and notes and media and citations that RM really uses for the primary name are associated with the Person record and not with the Primary Name fact.
I will grant that changing the name in the Primary Name fact also changes the name in the Person record and vice versa, so it’s very confusing. But the note and the media and the citation in the Person record are totally separate from the note and the media and the citation in the Primary Name fact. There is nothing you can do in the RM user interface to swap out those items with each other. The only thing you can swap out are the name, note, media, and citations between the Primary Name fact and an Alternate Name fact.
When I first started doing genealogy, the software I used really only supported things like citations and notes and media to be associated with the Person record. I fairly quickly switched to a piece of software called Family Origins which was a predecessor to RootsMagic and which had the same author. I was excited to discover that Family Origins supported citations and notes and media for facts, and this kind of support has continued into all versions of RootsMagic. So I quickly started attaching things like citations and notes and media for birth to the Birth fact, and similarly for all other facts.
That left me with the puzzle of whether the same citations and notes and media also needed to continue to be attached to the Person record. Through the years, I have come to the conclusion that the answer is mostly no. The one exception is that I still attach citations for a person’s name to the Person record, because there is no other place to attach such citations. The Primary Name fact would seem to be the perfect place, but as I have already described, the Primary Name fact does not work for that purpose.
The full story is that if I have any citations or media or notes about a person’s name that are even remotely complicated, then I use a custom fact I call Names. This custom fact provides the needed attachment point that is not provided by the Primary Name fact. And it reads better than the same information when attached to the Person Record because I can place my Names fact at the beginning of my fact list whereas notes associated with the Person record print at the end of all the person’s other facts in narrative reports.