Not all pieces of wood take a finish the same. Different cuts, veneer, end grains, all all can take finishes quite differently.

Wood comes from trees. Many trees in the forest. Each branch of each tree can have wood that looks different than another. The hallmark of something made with real natural materials is variability, not plastic sameness.

The difference was there before the treatment so why would it be any different after the treatment?

Should the person doing the work not be expected to notice and attempt to improve the situation? Would an extra coat of stain on the light sections help? All wood furniture is made from individual trees but most cabinetry does not show this much variation.

I realize there is natural variation within wood and appreciate that. I'm not looking for "plastic sameness".

However, the variation looks stark.

All photos/examples of white oak cabinets I've seen have slight variation in tones, not one this extreme.

The difference before the treatment was slight.

The ones you have seen are likely rift sawn vs plain sawn. You cannot make up for different sawing characteristics with stain.

Here's another cabinet with same issue of doors being much lighter than frame after treatment-

I think your cabinets are beautiful, but the result is probably due to the original color/variety of the wood.

I'd go to a cabinet maker and ask if he can provide new doors finished to match the rest of the cabinetry. Maybe not, but might be worth a try.

Agree that a skilled finisher should be able to modify colors/tones to a certain extent .... while still leaving plenty of variation as you would expect with natural wood. Other instances where this might be done incl. tweaking color of new floor boards to blend into old 100 yr old wood floor.

Can I ask what stain you used?

Love the stain color. What did you use?

The stain guy did a custom paint wash and it looks great, but it took a few applications to get right tone as you can see from problems after first wash only (prior comments).
However, I gave him a guide I found from @roserock918 instagram account.
I'll post the guide below:

Do you have photos showing the cabinets with the custom paint wash?

Also, thanks for posting the guide - while a professional cabinet finisher will know how to do this without needing a guide (as bry911 has explained above), it will be very helpful for diyers + people who are building (or renovating) a house and their builder/contractor uses painters instead of cabinet finishers.

It's great that you're seeking advice on Houzz regarding your bathroom cabinets. While slight variations in color between cabinet doors and the cabinet box can be expected due to the natural characteristics of wood and the staining process, a significant difference may indicate an issue with the application or the quality of the materials used. Before discussing it with your contractor, ensure to document and communicate your concerns thoroughly. Requesting their expertise to assess the situation firsthand is a wise step. Additionally, consider exploring professional forums or seeking guidance from experienced homeowners who have encountered similar challenges. Their insights and suggestions can offer valuable perspectives on how to address and potentially resolve this issue effectively.

OP, kudos to your refinisher for being willing to learn and improve their skills! Not all are as open minded and willing to work with a homeowner to get the desired results. Love the whitewash recipe - will be making use of it for floor project.