Why do the name of my partitions changes after reboot when I partition a LUN on multipath with fdisk?

Issue

• Why do the name of my partitions changes after reboot when I partition a LUN on multipath with fdisk?
  I do the following:
  1. Add a LUN detected by dm-multipath (say "disk1");
  2. Add a partition to the LUN with "fdisk /dev/mapper/disk1";
  3. Refresh the partition table with "kpartx -av /dev/mapper/disk1";
  3a. file /dev/mapper/disk11 is created by step 3
  4. reboot
  4a. The partition device has been renamed disk1p1

How do I make kpartx generate the definitive name (disk1p1) instead of one that will disappear at next reboot (disk11)?
or is this the default behavior of kpartx)?