I have this colocasia Calidora elephant ear that has ONE (healthy) leaf that has been slowly turning yellow since I got it and is now full blown yellow. My thoughts were overwatering or root rot, but neither is true for the plant, plus every single other leaf and stem are healthy and it sprouted a new leaf just this week. I’ve had it for maybe 3 weeks. The first pic is the day I got it (spot the yellowed leaf pre-yellow in the bottom right), second pic is about a week ago, and the 3rd pic is today. Please help I’m afraid I’m killing it some weird new way