The stair treads at a hotel in Boise darkened after 4 months, check your finish schedule
I did a 14-step oak staircase for a new build back in March and the client called me last week, said the treads looked like two different woods side by side. The difference was clear when I walked in, the landing and bottom 3 steps stayed light but the upper runs went almost honey brown. Turns out the GC let the painters use an oil-based poly on top of my water-based sealer without telling anyone. Has anyone else dealt with the finish reacting that fast, or is it just a pigment thing?
Ran into the same thing on a red oak rehab last year, the homeowner's handyman slapped oil poly right over my water sealer and it turned orange within weeks. The top coats just don't play nice together, the oil pulls stuff up through the water base. Your photo would help but yeah, that fast reaction sounds about right for that combo.