Terror Hound unable to summon.

[b]What operating system are you playing the game on? Windows, Mac OS, Android, iOS, or Playstation?
I am playing on iOS IPhone 6

What game version are you playing? You can find the version number on the title screen in the lower left corner.
I am playing version 2.1.5

So the terror hound morphs into the thylacine at the start of battle, even if it is the only creature in your party. That being said, even when alone, I am unable to cast any kind of summoning spells, they just fizzle. Is this an intended feature?