WaterReflectionDefinition with the rotation as defined bellow, don't seem to select the same variation frame as the main graphics when rotating, even though the number when the number of variations is the same so I would expect them to rotate the same way. The four cardinal directions work fine, but when you introduce more directions the two graphics select different frames.
Here's a clip made by Hanodest showing the frame number of the main graphic and the reflection graphics. Also notice how the two often switch orientation at different moments from each other.
This is probably related to the fact RotatedAnimation has apply_projection field, true by default, which changes which frame is displayed at which orientation so an animation with constant rotation speed looks better with the game's camera angle.
Water reflecrions however don't have that, which makes them be out of sync with each other
I can... kind of fix this, but it's never going to be perfect. Unit rendering has several different animations depending on what the unit is doing and depending on its state the orientation of the animation won't always match the orientation of the reflection (the way reflection converts orientation to frame index is not the same as how unit converts orientation to frame index) and if I change one to match the other it will break other stuff.
If you want to get ahold of me I'm almost always on Discord.