Is the soil touching the plant? That's what was happening when I lost my last AV. Wicking and watering from beneath is a good way to keep the soil wet while not risking accidentally wetting the leaves. Keeping them too wet, is a real problem too (found that out as well). You water, the soil is wet, and then over the week it should become dryer, and then it should be watered again when the soil is nearly dry. I would say use less water and see that there is a little "moat" around the main stem. I am no expert, I just started trying to care for them again.