Hi there,
Are you letting the medium dry out between waterings? Are the leaves in question being deprived of light? Those two seem the most obvious at first glance. I usually remove any leaves that arent catching the light, they will droop like that and be a little more pale than the others. You may also have some sort of lockout developing based on the discoloration I can see. Usually a high ph is the culprit.
Hope this helps