Was this a ready-to-finish piece or did you build it yourself? If ready-to-finish, do you know the manufacturer? Do you know what wood species the top, face frame, doors, and sides are? Top, side, and door graining looks very different. I'm guessing the sides are a veneered product (either solid core or particle board plywood). If so, the sides would most likely take finish differently than solid wood.
I've gone out to find myself. If I return before I get back, have me wait for me.
"Sawdust is Man Glitter"