What I expected:
To be unaffected while flying through flowing water.
What happened:
The water dragged me whichever way it was flowing.

To reproduce:
1. Find or make some flowing water (much easier if the water body is at least 3*2*2).
2. While flying, lower into the water making sure not to touch the bottom.
3. The current drags you whichever way it's flowing when you should be unaffected.

Note: water only, not lava.