Water from old chunks don't properly propagate into new chunks

The Bug

Water from old chunks intersecting newer chunks after blending doesn't properly propagate into the new chunks

Reproduce

• Make a world in 1.17.1

• Fly around

• Leave and open the same world in 21w43a

• Fly around where the old chunks meet the new chunks

Observed Result

The water didn't propagate into the new chunks

Expected Result

The water would propagate into the newer chunks