Put the summary of the bug you're having here
What I expected to happen was...:
Farmland stays as farmland for a game day or so
What actually happened was...:
Farmland reverted back to dirt within about 30 seconds, didn't even have time to hydrate
Steps to Reproduce:
1. In middle of ocean made a dirt platform, dirt 1 layer thick, made small rock house in center
2. Used iron hoe to turn dirt into farmland with two rows of dirt around my rock house
3. Went inside house to get wheat seeds, farmland reverted back to dirt before seeds could be planted
Cannot reproduce in 1.13-pre2.
In a 10x10 platform in an ocean, all blocks in range of water turn into hydrated farmland successfully while the blocks out of range turn back to dirt accordingly at the same rate.
EDIT: Uploaded gif of described behavior (platform was actually 11x11)