Minecraft v1.16.4
Forge v35.1.13
Simple Farming v1.3.5
More Waterlogging v1.4

If the mod More Waterlogging is installed, the fruit trees will generate with waterlogged leaves.

I haven't got the waterlogging mod installed, and I'm getting the same issue. Only happening with Simple Farming leaves. Currently doing more testing to try and see which mod is causing it.

Oops - did have more waterlogging installed. Sorry, new modpack. I can however confirm that it is these 2 mods together that are causing this issue. Did you want me to report this to the more waterlogging mod author ?