The little flash drive that couldn't

Might be a partial partition, ergo, where there is unallocated space in the partition table.

Try this:
Copy everything you want to keep off the USB
win+r, type "Diskpart".
Type "list disk"
Identify your USB (should be a size not exceeding 10GB).
Type "select disk <n>" where <n> is the number you got.
Type "clean"
Type "create partition primary"
Type "select partition 1"
Type "format fs=ntfs quick"

After it done:
Then unplug and replug the USB. It should now appear with correct size. If it don't appear, check diskmgmt.msc and assign the memory a drive letter.

@sebastian I'm not on Windows, but I had no idea it had a CLI partitioning utility. Cool.
I did check and the partition is as large as possible.
This is one of those promotional flash drives you get in press kits and swag bags. They're always broken in some way.
It was probably made by an unlicensed chinese company that used Transcend's VID & PID (or even in their factory).