Nope. Just went to a user’s page and hit message. The first post does have private_message set for the archetype, just not any of the subsequent replies in the PM; they’re all set to regular.
I did just find something really interesting. This is actually a UI bug, not a backend bug. When creating a reply, a POST is made to {discourse site}/posts with the following form data (formatted with linebreaks for your pleasure):
raw=this+is+another+reply+iok+asldfkjad
&unlist_topic=false
&category=
&topic_id=177
&is_warning=false
&whisper=false
&archetype=regular
&typing_duration_msecs=2000
&composer_open_duration_msecs=6168
&reply_to_post_number=6
&nested_post=true
Note how the UI is specifying archetype=regular in the post! I did some hacking and modified that same request to send archetype=private_message, and volia! The resulting event data has archetype set to private_message. For fun, I set it to archetype=shits_and_giggles, and guess what? The resulting event also had archetype set to shits_and_giggles.
I’m rather surprised that UI code is providing data about the post and that discourse is sending that data back out without even validating it. It really seems like that data should be provided by the server, not the UI.
So, now that I’ve figured out where the “regular” value is coming from, could this be logged as a bug and fixed? Or point me to where the UI code is for this and I’ll see if I can figure out how to fix it?