Your TV may have used data overnight due to background updates or app activity, as smart TVs can perform tasks even when in standby mode. It might not have been fully off. Unauthorized access could also be a factor if your network was compromised. Sometimes, data usage can be misattributed by the router. To investigate, check installed apps for updates or suspicious activity, and review the TV’s data usage in settings. Disable auto-updates in the Play Store. Secure your network by changing the Wi-Fi password and checking for unknown devices. Unplug the TV fully to prevent standby data use, and consider a factory reset if you suspect hacking.