I am sorry for this delayed reply to your gardening question. The spring rush has brought a deluge of questions and we are working hard to catch up!
I think the soil stayed to wet along perhaps with being exposed to an air draft. Repotting possibly caused some wounding of the roots that let in a rot but this usually needs wet soil conditions to happen. When you repot take care not to overwater or keep the plant's soil too moist.
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!
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