Not many doors go well with tyvec. It will look better with a finished surroundings.

It looks lovely with the brick. Questioning the application of the stain.

Take a look at the can of stain. Most, maybe all Minwax stains are interior only.

Stains are typically one coat.

Many house painters lack the knowledge, skill and experience to stain this type of door.

What did the door look like pre stain?

Will there be a clear top coat of something?

The problem is there is nothing to practice on.

" applied wood conditioner and first coat of minwax dark walnut stain to this beautiful mahogany door "

Minwax wood conditioner and stains are INTERIOR ONLY products as PPF mentions above. Wood does take stain differently and the bottom rail is an indicator of that. Also do not allow him to put a second coat as that will only make it worse.

A lot of the future durability of an exterior finish will depend on whether any of the surfaces get direct summer sunlight exposure to cause UV degredation. No direct sunlight will make future maintenance less frequent.

General Finish 450 water based wood stain followed by 4 coats of 450 Exterior Topcoat in a matte finish is one path. The stain has UV absorbers and mildewcides to prevent greying and mold. The topcoat dries with a low sheen and is highly flexible to prevent peeling from thermal expansion. Includes UV absorbers.

Your existing situation involves finding a solution for the blotchy areas and getting an exterior finish on. Now, while the stain, if oil-based, hasn't fully cured the blotchiness might be lightened by gently scrubbing with a medium 3M Scotchbrite pad the dark areas in the direction of the wood grain and immediately wiping with a lint free cloth. Any small areas that get too light can be tinted with small amounts of the original stain using an artist brush.

To get 450 topcoat to adhere to oil-based stain you have to let the Minwax completely dry for 72+ hours. Then use 50/50 water anddenatured alcohol to clean the surface. No lacquer thinner. Scuff the surface lightly with 220 or 320 for grip. Remove all sanding dust with a vacuum and damp cloth. Apply thin even coats with 2-4 hours between coats. Sand lightly between coats with 320. 3 coats max according to General Finish. Follow the recommended maintenance recoating schedule based on sun exposure.

My impact/hurricane rated front door was custom made by a local woodworker. Might not be obvious by the photo but the door and sidelites are 10 ft tall.

It was stained at the shop before it was brought to my house and installed. He had plenty of scraps of the same wood for us to test different stains.

Wood is wood, so there will always be areas with different grain that takes stain differently.

You have no idea what it's going to look like until the top coats are applied. It will, most likely, change quite a bit. Testing of stains should be done in scrap wood or unseen surfaces as close as possible to the wood you actually intend to finish. All steps in the finishing schedule, including all sanding steps, need to be done to have any sort of accurate idea of what the finish will look like. I'd guess your door will look a lot better with a finish coat applied.

In general pigment stains like Minwax are a terrible choice for coloring wood, especially if applied to raw wood (good that your painter used a conditioner) They are an excellent choice for creating nice effects with grain fills after the wood has been colored with dyes and sealed. Blotching and unevenness is extremely common using these products on raw wood unless they are applied like paint, so heavily that they obscure the wood.

I'd always prefer to choose a wood that is the naturally the color you want, though with an exterior door walnut will quickly fade to a light brown. If you want a dark brown I'd start by coloring the mahogany using a light resistant, metallized complex dye (TransTint brand is good) applied with a sprayer to achieve uniformity, then a sealer like unwaxed shellac, filling the grain with a dark colored filler if you want a flat surface, finally a good quality spar varnish or other suitable outdoor clear finish.

Depending on your climate and exposure of the door maintaining a clear finish can be a time consuming enterprise, requiring regular attention. Paint is very often a better choice.