It could be. It rotted through no fault of your own.
I always started my cuttings in straight Miracle Grow potting soil. One or two out of twenty would fail to root. I would water a bit on planting. Keep them fairly shaded and only watered when the soil started to become noticeably dry. No fertilizing, no misting.
You are living in one of the most humid places on Earth. There is nothing to gain by misting.
