USB Sticks not getting properly recognized
There's nothing wrong with what you are seeing.  That's the partition scheme for your bootable USB.  When you format it, you are not deleting the partition, just "blanking" the active partition.

Formatting a partition is not the same as deleting the partition.

To get back to a "single" partition (this is what I am assuming you want to do), issue this command in diskutil

diskutil partitionDisk /dev/disk3 1 GPT HFS+ NAME 100%

This command will permanently delete anything you have on the device.  Make sure you are using the correct device identifier

Be sure to replace "NAME" with the name you want to give to the USB.

Your drive partition map will be wiped, and the HFS+ (Mac OS Extended) file system installed.

What I suspect happened in your case is that you didn't "write" the new partition scheme to the USB.  This is done by issuing the "w" command.  Linuxhelp has an excellent tutorial on fdisk



More info can be found by typing man diskutil