On mobile, the server drops live stream events for backgrounded or
unfocused agents. When the user returns, a seq gap triggers a
catch-up fetch whose canonical entries are appended to the tail —
but the head was never flushed. Stale live items from before the
gap stayed in the head and rendered after the newer catch-up entries,
breaking chronological order. Worse, subsequent live events of the
same kind (e.g. assistant_message) would append to the stale head
item, garbling message content.
Now the incremental path in processTimelineResponse flushes head →
tail before reducing canonical entries, keeping the timeline ordered
and the head clean for new live events.
Mohamed Boudra