Flower Map affected by Y coordinates

When attempting to build four flower farms, I was dismayed to find that applying bone meal to grass blocks at different heights was producing different flowers. The first screenshot demonstrates this, with an Allium grown 4 blocks bellow a Poppy (both grown using bone meal). In the second screenshot, you can see another farm that should have contained Lilies of the Valley and Cornflowers (as seen on the ground level) but only the Lilies were produced when bone-mealing the raised farm. Everything here is within a flower forest biome.

It seems the flower map is now dependent upon the Y level, meaning 2D flower maps are no longer valid. This didn't seem like intended behavior, given the lack of mention within the patch notes. 

Thank you!