What could this be?

[ILS]

Thank you for your input I'm off to buy the neem oil and repotting supplies. Should I look for the leaves improving in color and appearance with the treatment or simply a reduction in the spreading?

On the second plant I'm going to repot it in a new medium and hope for the best. I'm not sure if to continue the regular watering schedule or add more fertiziler or not? I hate to see the leaves getting sooo yellow. I checked the roots and they look fine. I have it in a shady with late sun area?

Thank you once again. You are all soo very helpful!