In survival mode I was attempting to kill the ender dragon with exploding beds. After getting rid of the end crystals I placed two cobblestone blocks next to each other with a bed on top of them on the bedrock on the edge of (but not in) the portal where the dragon lands during her attack cycle. I then waited for her to land, and right clicked on the bed so that it would explode. This injured the dragon as it should, but after that she took to the sky again and refused to land on the portal at all. I relogged and the dragon was back to full health and was working normally but as soon as I Injured her with another bed, she flew away and is currently circling one of her obsidian pillars on a loop. She still has not come back down. I waited about an hour just to see if it would fix itself. It has not.