While soaking my Pardalis Pardalis tortoise today I noticed he was getting soft in the middle of his plastron. He eats fine and is showing growth but has been spending a lot of time in the humid hide lately. My other leopards are fine with hard shells but he is soft. He does not touch the Mazuri or Repcal pellets I put out for them (all 3 of the others do) and only eats lettuce & dandelion green which I sprinkle with calcium & cactus which I sprinkle with tortoise dust vitamins. I see him drink & poop, he is not shy and active most of the day and I soak him once a week. Temps are 100 in the hot spot, 85 in the humid hide and 75 at the cool end. Any ideas on what may be causing this, he is the one eating lettuce on the left side of the picture.