Leaving a chat stops its background scoring
Between turns, Bandicot scores which parts of a chat still matter. Leaving the chat or pressing Stop now ends that work instead of letting it run on unused.
After each turn, Bandicot asks a small model which earlier parts of the open chat still matter, so later summaries keep the right things. If you switched to another chat while that ran, the answers were thrown away, but the calls kept going until they finished.
Now leaving the chat, pressing Stop, closing it or quitting ends those calls at once. Nothing changes for the chat you stay in.