agent-shell v0.83.1 through v0.83.3 send every prompt you queued during a turn as one message, including after you cancel. On v0.82.2, agent-shell--prompt-queue-process-next took the first pending prompt and left the rest. I compared those files without running Emacs.

#791 asked for merge as an option and wanted one-at-a-time to stay the default. After v0.83.3, current agent-shell-prompt-queue.el has agent-shell-prompt-queue-merge, default t. The ERT with it nil submits just the filenames and leaves ("sorted by size") queued. The v0.83.3 tag still joins the whole list. GitHub Release objects for the 0.83.x tags 404.