I bought this Thai con about a month ago from a plant store. It looked beautiful and was in great condition. Since I brought it home, it has been slowly becoming more yellow in the two smaller leaves. The top right big leaf got a little burned (I think because it was too close to the window) but I have since moved it to a shelf with a grow light. I'm not sure how great the potting mix is that it's in but I'm afraid to add any more stress by changing it. Is there anything I can do to save the plant and keep more leaves from turning yellow? What am I doing wrong?
Thank you for your help!!
(Also these pictures are from about five days ago, the two small leaves have become more yellow since then)

You may have gone too far in light reduction. If it just came from a greenhouse it was used to pretty strong light and a grow light is not much like a greenhouse.
I wouldn't sweat it if it got a slight burn. The next leaf that grows out will be able to take the full sun. I think if you move it back to the window you can halt more leaf loss. You can cut off the yellow ones now.

Greenhouses have 360 degree multi- directional light, your house and grow light are providing one source of unidirectional light. Its probably not enough light. D0 you have a window you can put it in?

Also be careful not to keep it too wet.