Every time i save my Testworld and load it again, all my Sprinklers look like this:

I think there is a bit of confusion between the block rotation and sprinkler rotation in the code.
This bug should go away with the fixing of #27
Can you place the sprinkler in another direction and see if it sprays the same?

I've tried it with different directions, but after the reload, all of them sprayed in the same direction...

Yup seems all the NBT data is being stupid

This is probably because of ticksSinceChange(Flags.isClockwise)
This can certainly be fixed by removing the un-required networking.