Your plant is setting in water too long because the drainage holes are blocked from the bottom tray. Let the plant dry more between waterings. When you water, water until you get water to discharge out the bottom of the container, but don't let it set in water. . When you water your plant and the plant is setting heavy on the tray, the water can't exit or drain properly. The bottom of the pot is very wet, when the top is dry. I use mason jar lids to raise the pot off the ground to allow for good drainage on the bigger pots. Water until you get water in the tray and then dump the excess water and allow the top inch to dry well before watering again.