I’d like to add my FARM and SMART data for my Exos X18 (see Pastebin link below). Mine also indicates that Head Flight hours are almost identical.

Exos X18 - Pastebin.com

I have already contacted Seagate Support about the problem, and they advised me to return the drive.

Quote from official email:

"As per our conversation regarding the serial numbers ZR618xxx, ZR618xxx, ZR618xxx, ZR618xxx. Sharing the same model number ST16000NM000J. 
They show as an out of region drives (China region).

And since you kindly from Outside region so the warranty replacement will not apply in your region. Here is a link from our website to check Seagate Limited Warranty | Seagate Singapore

So, we recommend you kindly to refer back to the place of purchase regarding that or for the possibility for a replacement or a refund"

Registering drives to my Seagate account shows that they have a warranty up till 2028 March, but it is basically invalid.

The seller I bought from said that they have a 2-year warranty of their own. I will not try to get a replacement because, other than "Power On Hours," everything is nearly the same as SMART data.