Also if following laws of osmosis. If our rootball contains much higher amounts of salts than our plants.I 'm starting to notice this too. Some growers use these hot premix soils and in the first week dose them with a ton of nutes. I don't feed for the first three weeks; depending on the plants needs of course.
Feeding plants are like salting soup. You can always add more if needed but it's hard to take it out.
Then it means the soil is actually drawing moisture from the plant itself.
Salty media sucks every little bit of good there is from a plant @Yam.
Water is the molecule for life as we know it.
Don't starve your plant of water.