WHY DOES THIS HAPPEN?
The most common cause of this symptom is overwatering. In particular, it can occur as a result of a lack of drainage in your plant pot, or because the plant first dried up too much and then was overwatered.
This can seem counterintuitive, but when a plant hasn’t been watered for a long time and completely dries up, it can actually cause more damage to add a lot of water all at once. This is essentially because the plant is caused to drown, as when a plant has dried up, its roots are not able to take up water as easily any longer. Therefore, when you suddenly add a lot of water, the plant drowns in the water it is not able to uptake.
As for poor drainage, it is always a good idea to ensure that your plant pot has drainage holes at the bottom in order to promote good drainage and help prevent root rot. Similarly, you should make sure that the pot is an appropriate size - if your plant is potted in a pot that is too small, the roots may not have enough room, which can affect their ability to take up water.