Join Date: Jul 2011
Location: Caye Caulker, Belize
That looks like a burn/gouge mark from the factory belt-sander.
Any wood will soak up more stain/pigment wherever it has been sanded coarser than the surrounding area.
I find both cherry (wood) and oil based (stains) the hardest to work with for blotching.
Baltic ply at least used to be a premium product.
That burn mark looks to be near the factory edge, probably none in most of the panel, but re-sand everything evenly anyway.
Then try an alcohol or lacquer based stain, much less blotch prone, especially if you spray and do not wipe.