Endermen keep teleporting back onto magma blocks right after

What I expected to happen was...:
I would spawn the enderman on the magma block and he would teleport away

What actually happened was...:
he stood on it for awhile and then teleported away but then teleported back to the same block, this pattern repeated itself

Steps to Reproduce:
1. go to the nether
2. spawn enderman on magma block
3. wait