overwatering?

I think I may be overwatering. Heavy pots, every 2-3 day water cycle, super moist and cold about 3 inches- down. Yellowing mushy and curling sides of newer leaves.

I have 4 plants that I'm growing and 3 of them the Dos-si-dos33 Amnesia Gorilla skittles About 2 days ago I had to water them and now the coco coir is soaked and the leaves only have a tinge of yellow and still look healthy at the moment but slight drooping of outer leaves. They are 17cm high...

Seeds were started in happy frog in 72 cell trays. Had stretching problems so I repotted into solo cups. Have been using plain water. Is this burn or a watering issue? Thanks in advance.