Your aireplay-ng console is giving you the hint "mon0 is on channel #, but the AP uses channel 6". And so is the airodump-ng console with the message, "fixed channel mon0" message.
You should not be running kismet and aireplay concurrently. It seems to me that you didn't lock channel in Kismet and let it run while executing aireplay --deauth in another console. Kismet is changing your channel when you need it locked for deauth. Kill kismet and run --deauth again.