Seems to be the only double plant affected for some reason.

Could you give a specific example? I loaded up a test preset with the only resource being Plant(RoseBush,3,50.0,0,139,minecraft:grass_block[snowy=false],minecraft:dirt) and I got normal rose bushes

NewDefaults.zip

Plains biome:

Turns out, these are not rose bushes, this is every non-tall flower spawning as the bottom half of a rose bush. Should be a simple fix

Thought there were a few too many, thanks for figuring it out Auth.

World is back to normal ^^