When summoning a demon, if the demon crystal has a current owner it will not respond to commands (right clicking it). The demon cannot be tamed in this state, and must be killed and re-summoned. After being killed the crystal will revert to having no owner. Summons from this state can be tamed again and will, when killed, repeat the cycle.

To reproduce:

1. Summon and defeat any tamable demon with the arcane pillar/plinth structure.
2. Summon the demon with the dropped demon crystal.
3. Tame the demon with a weak blood orb
4. It will now respond to your commands
5. Kill the demon.
6. Now, when you look at the crystal, it will say "Demon's Owner: name"
7. Summon the demon and try to give it commands. They won't work.
8. Kill the demon to get back to step 2.

Tested with
Forge 10.13.4.1448
Blood magic 1.7.10-1.3.3-11
CodeChickenCore 1.7.10-1.0.7.46
NotEnoughItems 1.7.10-1.0.5.111