Etcher changes partition table from fat to mac?

I use Linux Mint. I’m trying to burn a Mint 18 ISO to a USB stick which has a GPT partition table and is formatted FAT-32, both operations performed using Gparted.
The burn using Etcher is always successful but on three separate USB sticks, the partition table is always inexplicably changed to MAC.
Can anyone tell me why?

Hey @Seedywee, Etcher executes a byte-to-byte copy of the image you’re flashing onto the flash drive, so whatever partition table or file system is on your drive, it will be completely replaced with what’s in the image file.