I don't really have much to go by, but in that location, I wonder; could it be too wet? I say that because corners like that can be places where water pools.

Iits currently in the basement around where the sump pump is, with humidity between 30 to 40. I believe I actually overwatered it. I am currently using florecent light at 6500k. Should I get better lighting?

I had a similar plant inside the other day. I was only very lightly watering it. If I were you, I'd let it dry out for at least a week if it's wet.

Right now its probably not loosing much moisture due to cool temps and relatively neutral humidity levels. I think Jedoba is right. Too much water.