Christine_ASUSI didn't use USB tethering much, used hotspot mostly which has this issue as far as i know. Not a major one to downgrade OS though.
After checking, for the users who have concern about the Mobile Data Usage counting while using USB Tethering, please refer to your linking PC for data counting or downgrade your device to Android 9.
We apologize for any inconvenience caused and your valuable advice will be included in future design and optimization considerations. Thank you.
#ZB602KL Firmware Spot
#Android 10 to Android 9 Guide