I used a seed from my old world I created in 1.10 to check out new 1.13 Snapshot features (which I love btw, nice job!) and upon flying around I noticed that all the Flower Forests that WERE there were totally erased and replaced with regular Forests.

Since this seed is of a world I've been playing for 2 years, I know it well, so I checked in other locations and those Flower Forests had also been erased. But every other biome, as far as I can tell, were in the correct location. From Mooshroom to Mega Taiga to Mesa all generated just fine.

I tried other seeds from worlds that were generated in 1.11 and those Flower Forests were erased too in the 1.13 Snapshot.

Then I tried a seed from 1.12 and those Flower Forests were right where they were said to be in the 1.3 Snapshot. So, I believe there is a major bug that erases Flower Forests in worlds that were created before 1.12.

I'll included pictures of my findings. I really hope this gets addressed before the update as Flower Forests are my favorite and I'd hate for them to be erased when I transfer my older world to 1.13

• One picture shows the seed from 1.10 generated in 1.12.2 - Notice the Flowers, Biome name, and Coordinates.

• The other picture shows the exact same seed updated to 1.13 Snapshot - Notice NO Flowers and the Biome changed, even though the coords are the exact same.

• Notice that in all the pictures, the other biomes around it are exactly the same, with only slight surface changes between the older and the snapshot

• A third picture shows half the area generated in both versions and there's clearly a chunk border.

Thanks!! Hope it can be fixed! >_<