Endermite suffocates when going off-rail

I tried to build an enderman XP-Farm, and It now happened 4 times in a row until i finally figured it out. A lot of Nametags and Emeralds later, I realised that the manually spawned Endermite takes damage from driving off the two placed rails. Wich makes it unable to continue my work.

Pictures of the damaged Endermite follows, as I am able to grind enough Enderpearls.

Greetings Freddy