It’s actually a FAT32 limitation not a FCP/MAC limitation (might even be a FAT32 on a PC limitation). Seems to me, on a MAC, I was able to get larger files on there, but then trying to transfer to a PC, everything started reading and writing as if the disk was locked and saying I didn’t have access. A real pain.
Thumb/flash drives are all formatted FAT32, that’s why they can be used on both PC and MAC, but because most of them are under 2gigs the limitation is never hit. MAC uses its own formatting system and most newer PCs use NTFS. These can both handle some hefty file sizes but they don