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! >_<
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Please provide seeds and coordinates for your examples.

Seed: 554762737523904
Flower Forest -394, 118, -353

It's resolved as a "Duplicate" (you can see the resolution type after the text "Resolution"), and you can see under the heading "Issue Links" which report this one duplicates, being MC-125037.
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