Welcome, tm. It still sounds like too much water. These need to dry out completely between watering. And even then very sparingly on the water. I would also turn the plant pretty often (every few days) in that window to let all sides get some direct sun. When these plants are happy, they are hard to stop from growing but when they are unhappy, they do let you know it.
Drama Free Zone.
What every gardener loves the most, Begins and ends in rich compost. (Tina)