What I don’t quite understand is why array was used here in the first place instead of equation* or similar.
Anyway interesting post I wouldn’t have guessed that carries onto the next array.
Why does it only affect the first cell (or first part of the first row) though instead of the whole row?
It was a third hand file with a lot of packages and the content was quite different, so perhaps there was a good reason in the original file that was lost in the minimization or perhaps the problem is that sometimes people prefer to reuse a few environments for all the possible constructions.
About the first cell: IIUC You can determine the color by the row, the column or by the individual cell, so the color is recalculated in each cell. For some reason, it fails in the first cell. I'm still curious.
Anyway interesting post I wouldn’t have guessed that carries onto the next array. Why does it only affect the first cell (or first part of the first row) though instead of the whole row?