@Robin_Yang: I just replied to your email to support as well. Usually, if Insync is done with the initial local folder scanning, the new changes are queued as soon as they are detected. In your test, before updating/deleting files, what was Insync’s state, was it the animating tray icon or a stable green checkmark/error icon? We request you to conduct test after Insync has reached a stable sync state after the start.
Could you send across the Insync’s logs.db and out.txt files from your machine so that we could check if there are any network/proxy issues in your setup? See: how to find logs