I just came accros this topic and want to add my findings.
I bought a SANDISK Cruzer Ultra Flair 3.0 128 GB, which didn’t let me copy files larger then 4Gb. (on windows and linux)
Trying to find an solution I read about the three file systems and their differences: Fat32, exFat and NTSF.
Two different windows computers showed that the usb-stick was formatted as exFAT.
As a test I tried to copy an .iso file from 4.7Gb to the stick. All attemps failed, a message stated: the file is too large.
Then I re-formatted (slow) the stick in a windows computer to exFAT.
After that I was able to copy the 4.7Gb .iso file to the usb-stick.
It looks like as if Sandisk is using a modified exFAT file system, perhaps to support their SanDiskSecureAccess environment.
(as a result, customers are not able to share easily (high resolution holiday ) movies among each other)
It would be nice to know if it is a modified exFAT file sytem or not.