При продолжительной работескорее всего это проблема про которую написано в оф доках https://docs.python.org/3/library/asyncio-task.htm...
Important Save a reference to the result of this function, to avoid a task disappearing mid-execution. The event loop only keeps weak references to tasks. A task that isn’t referenced elsewhere may get garbage collected at any time, even before it’s done. For reliable “fire-and-forget” background tasks, gather them in a collection: