Quoted from j_m_:John_I:
your displays look like they came from completely different manufacturers, let alone different batches. that's really odd, because for the 20+ panels that I purchased from ali express, I never had any issues with the level of brightness between 2 panels.
As I mentioned, the difference is not nearly as dramatic to the naked eye - even to someone with perfect color vision. For some reason my camera really exaggerates it. I showed the picture to my friends who can see the difference and they said it is noticeable, but not like the picture fortunately.
I have two more panels coming for a clock I am building for a friend. We will see how those look.