Was your substrate the same? Different thicknesses and suctions will give different drying out colours.
I did a rubble stone cottage back in 87. A window was took out and the bricklayer blocked it up 10mm set back from the existing render. Then the render was hacked off and it was 6 coats thick!
I must have put on 25mm scratch coat just to be level with these blocks. The blocks had two thin coats of render and a dash finish. The blocked up window dried out first and looked bare of pebbles. The customer did not accept my explanation and that wall was not paid for. That was in October 1987 the night of the storm. I went back the following May and it looked fine but he said on wet days it looked wrong. I explained it would because of different density's but still could not get paid.
Oh dear! Another Volkswagon Golf needing a respray because of vandals keying it.