While mining in the new pre release, I placed a bucket of water above glow lichen, and the water flowed over and around the glow lichen, but not through it. I decided to test it out again, and recreated the scenario in a superflat world, which I have provided a screenshot for.

Expected result: Water logically flows through glow lichen, destroying it.

Actual result: Water defies gravity and flows around glow lichen

Steps to recreate:

1. make a 3 to 4 block tall wall, 4 works best.
2. place glow lichen on the 3rd block, or 2nd if you went for a 3 block tall wall
3. (optional side coverings up diagonally from the glow lichen, not required, but helpful to see the weird water flow)
4. place water directly above glow lichen and watch as it flows over the top of it.