file dates are lost on copy operation from Window 10 file explorer

I copy files from my Windows 10 machine using the file explorer to the mapped USB storage device on my router.

I find the files on the USB storage device have timestamps of the time of copy (not the file create/modify/read timestamps).

Fireware:  V1.0.4.120-10.0.91

Is this the expected behavior?

I copied about 35000 pictures in the 65GB backup of my win10 machine.

Now when I try to view them chronologically (to find a 3 month old photo) - well I just can't!

What reason would anyone designing a file copy behavior think changing it's timestamps to be good behavior?

Thanks, Morris

I think it might be time to get a new router.

I like ReadyCloud but this behavior...