Not to go too much further in the weeds, but I have a dear friend involved in animal husbandry who was worked extensively with tigers. His experience is that while most big cats thrive in captivity with consistency, tigers require regular changes in surroundings, scents, sounds, and other stimulation to keep anxiety and stereotypical behaviors from setting in. He travels occasionally with his cats for movie and television work, and having been fortunate enough to spend time with him on some of these locations its clear that they settle in with new stimuli to explore.
AK rotates their population between the two yards with different enrichment to attempt this, but there's only so much that can be done to avoid the sameness.