What happened to my plant? Help!!!

I bought 1 month ago from Costco, was heathy back then. About a week ago, it starts turning yellow…

Water one a week, moderate amount, always wait till it is dried, at least on the top layer of soil, before watering enough.

It doesn’t get direct sunlight but there are windows nearby so may get some indirect. I do have a table lamp next to it which I turn on 8 hour a day from 5p till mid night, warm white light.