Sorry for all Inconvenience you had to face and your client had to face, you're right this is not a mistake by Asus and also it's not a common issue which occurs in general.
The Hard Drive either HDD or SSD which is used in that specific Device/Laptop is possibly used in another device which was in charging, means A motherboard of other system is connected with harddrive of that laptop it can be done for any purpose either to check harddrive is working or not or any other reason.
Windows is a software and as it keeps logs according to the use of Hardware too through BIOS it cannot have overwritten data or false data recorded.
---------
--If the reply is helpful, please Upvote and Accept as answer--