Hello, I am playing with Water (Lake/River) system.
Lake does not display water material, but River is ok
   
and why, there is no bumb effect on water in play mode while material preview has it

there is a silly trick with the lake, the point needs to be clock wise ( or counter clockwise, but one or the other )

as for the bump, i think its only supported in certain mode

Bump currently works only for "Water/Ocean" but not lake/river

@RedcrowProd
Wow, it works, why not put this trick in to official document ?

@Esenthel
Where is that "Ocean" option?

You can access it through code "Water"