Based on the label, I assume they are supposed to be 256 GB? The drives are likely much smaller and controller lies. NTFS stores multiple copies of the metadata across the drive, FAT only stores stuff at the beginning, so on a formatted drive you won't know that something is wrong until you write over the real physical size.
There is software that does full testing with random data and no FS, that will tell you the real size.
The other issue is reliability. If someone goes to the trouble of creating fake flash drives I do not see them using the better quality components within, including whatever flash memory IC they choose to use. I would not be at all surprised to see production line rejects (scrap) used for the flash memory. Such QC fails are not something I would want to trust my data with. Using junk flash memory is more trouble than it is worth in my opinion. If a USB stick turned out to be a fake I would chuck it in the bin without hesitation. Having such knocking around my workspace is just asking for data loss so why bother risking it ? A flash memory IC may pass a single, or even multi run test, but that does not mean it will not suffer from flipped bits over time.
Longevity of data retention before corruption is a whole topic on its own but I generally trust hard disk drives and DVD-R over flash technologies. I remember people saying CD’s would become unreadable in 10 years due to data corruption through silver layer failure. (It was new technology at the time). I have music CD’s from 1987 that still play fine thanks to them not degrading as feared and the data correction algorithms of a CD player. Flash does seem like a more ‘fragile’ data storage technology in terms of longevity though. That said, EPROM’s seem to retain their data very well and they only had a predicted 10 year data retention life.
it is perplexing why anyone would even bother to make misreported flash.
I think what happened here is maybe reject 64GB sd cards got used for some sort of ECC 32GB about drive that fails past 32GB.
on Amazon.
I do not bother with a RAID NAS as I have had to repair a few of those with controller failure over the years !
I might suspect that being for 'Windows' , 'Android' and 'Apple', the only file format that is compatible with all is FAT/ExFAT. So internally, the controller may only support this file type?