Hi there, kindly let us know which firmware version your device is on.
Also in order to help you better kindly help us with the following details:
1. Kindly let us know the Charging time taken from 0 - 100%.
2. What's the charging time difference between the current & previous update.
3. Try another charger & let us know if there is any difference.
4. Use the ASUS charger on a different phone & let us know the difference.