With parted, fdisk, gdisk, etc. you only change the partition table on the disk. Since your old partitions are still in use by your system, it keeps using it with the information (start sector and size) it got at boot.
With parted, fdisk, gdisk, etc. you only change the partition table on the disk. Since your old partitions are still in use by your system, it keeps using it with the information (start sector and size) it got at boot.