Finished answers no longer stick on "Generating response…"

When an agent answered you, the message could end up finished and empty of the answer: the bubble still reading "Generating response…", with nothing to indicate anything had gone wrong. The round had completed correctly — the answer existed — but the message never showed it. From the outside it was indistinguishable from an agent that had hung, and waiting or reloading did not help.

The same fault had a quieter form: a streaming answer that stopped growing after its first words while the rest of the reply was being written. Both got more likely the busier the server was.

Why it happened

Everything written to a node — each chunk of a streaming reply, then the final answer — goes through one ordered queue, and each write is sent as a small description of what changed relative to the version the writer last saw. The queue did not wait for confirmation that a write had been stored before starting the next one, and the next one read the node's last confirmed state. Under load that state was one write behind, so a write described its change relative to a version that had already moved on — by its own hand, a moment earlier.

The owner of the node is right to reject a change described against an out-of-date version: that is what stops two people editing at once from overwriting each other. But here there was only ever one writer, in order. So the final answer's text was rejected as a conflict with itself, while the rest of the same write — the "finished" marker, the usage figures — was accepted. One write, two outcomes, and no error anywhere: hence a finished message with no answer in it.

What changed

Each write now builds on what the previous write in the same queue actually produced, rather than on a view of the node that has not caught up yet. The instant the node carries anything newer — a confirmation, or a change from a genuinely different writer — that newer state takes over again, so real conflicts between real concurrent editors are still detected and resolved exactly as before.

What you will notice

A message that says it is finished shows its answer. Streaming replies keep growing to the end, including on a loaded server.