Rori said:It's definitely overwatered. And with these spots it looks like some type of fungi has developed. I suggest you treat it with a systemic fungicide and water it only when you see leaves drooping + checking the soil to be very dry. More light would also be beneficial!
WillC said:Your Marginata does not have a fungus problem and does not need a fungicide.
The original leaf yellowing was not because it was rootbound and needed repotting. It probably was not getting adequate light in the bathroom and it may not have been watered properly. Repotting would not solve either of those issues.
Unfortunately, the repotting may have caused some additional issues, depending on how you did the repotting.
Please post a photo that shows how it is now potted. When you repotted how much of the original soil did you remove?
kxhsing said:
Thank you for the diagnosis! Is there a brand of fungicide you would recommend (or home remedy)?