Dragon problems

When I enter the end, no dragon spawns. I cannot spawn him in with ender crystal build. This happens in every world, except servers. This happens in Minecraft vanilla and optifine and cape mods. You can spawn him with command blocks, but he is stationary, takes no damage, and shows no purple health bar. He does make sounds and appears to take strength from ender crystals.
All other elements of the End are normal. I have a windows lenovo think pad that is somewhat beefy and can run optifine fairly. Please look at the screenshots I included. Thank You!