Farmland moisture state jumps from 0 to 7 when hydrated

The bug

When Farmland is near water, the "moisture" block state jumps from 0 to 7, instead of gradually changing its value like when water is removed.

What I expected to happen was...:
The moisture state to gradually increase

What actually happened was...:
The moisture state jumped from 0 to 7

Steps to Reproduce: MC-265476.mp4
1. Open your debug screen (F3)
2. Run this command

/gamerule randomTickSpeed 30

3. Place a Farmland
4. Place water next to it
5. Look at the "moisture" block state of the farmland
See if there is a transition between 0 and 7
6. Remove the water and repeat step 5