Is it sealed inside a box or cabinet? How much ventilation is there? It could be outgrowing the available dry air supply. Doesn't look too bad yet, I don't think it should harm them permanently.

What do you mean by some leaves discharging water? Are the leaves becoming wet, or making the inside of the box wet? That doesn't seem ideal to me.

The flow of sap is driven by the suction of water transpiring out of the leaves, and if the air is too humid to take any more water the leaf can't sweat properly, and the nutrients aren't sucked up from the roots as quickly.

Also, diseases become more likely after a while in damp conditions.