I went to check out the dragons in a Zodiac habitat that is located on the largest island, in the uppermost (top) corner of the game, and I am not able to select that habitat at all. Which means I can not move, feed, etc. any of those dragons. Nor move or upgrade the habitat.

I'm not sure when this occurred. I just noticed it now. My game downloaded the new land upgrade today, not sure if this is a coincidence or not. I haven't noticed this with any other habitats, or any other issues.