I’ve been building a pair of floor to ceiling cabinets for my son. Cherry ply for the carcases. I didn’t see the problem until I put a coat of Watco on, but a very prominent horizontal surface has a 3/16″ or so wide dark line running from the back to the front. As near as I can tell, there is a 1/8″ or so gap in the substrate beneath the surface veneer, and interferes with the color of the surface. It looks awful. I tried bleach. Nope, it didn’t work. I tried steaming it, to raise any depressions, ditto. Still ugly as sin.

Please share thoughts about how to fix it? My best idea so far is to redo both pieces [so they match] covering the horizontal surface with some new cherry veneer from Rockler.

If I do that, I’ll sand down the oiled surface, but then what glue is likely to work best?

Thanks to all who answer.