Now that you guys pointed it out, I checked mine and found the "QWERTYU" keys do have inconsistent textures, both on the top and on the side. It is not noticeable without harsh light hitting the caps, though. I wouldn't necessarily call it shine, but definitely texture differences.
Honestly I don't know how to feel about this. I purchased several other GMK sets currently in production, so I am concerned if those sets will have similar issues or worse issues. I still wouldn't call this a "disaster" because as far as I know, there are no other major issues of this set, and the spacebar is not warped.
For the comments on GMK, I don't think making them "too successful" is the issue. Sure, their workload has increased tremendously with almost half a dozen GB's every month, but I think that should make them more serious about delivering a good product rather than taking it for granted. Changes are going to happen within GMK to deal with the increased workload, and the byproduct of that may be what we are seeing right now. Also not to mention complications due to the current pandemic...
As usual I see people jumping on to conclusions faster than a diving champion and assuming the worst. Inconsistency of texture is a valid complaint, but I am afraid painting GMK as the villain on a 14 year old, out-of-date (though still useful) forum is not going to do anything. If anything is going to help, as least communicate this to the vendors that you purchased the keyset from. Judgement without understanding is just junk banter, and pointing fingers is not going to do anything good.