I just had an issue with this on snapshot 17w14a. In the two tests I did, I had a dispenser place or pick up the water or lava. In both tests, the observer fired both on the initial placement of the liquid and on the next "flow tick"*** for lack of a better phrase. I don't have redstone connected to the observer, it fires directly into a piston.
: Just a phrase I came up with representing the amount of in-game ticks it takes for a liquid to flow. The amount of time it takes in ticks for a liquid to go 1 block is a "flow tick"
Sheboigan Bruh
I just had an issue with this on snapshot 17w14a. In the two tests I did, I had a dispenser place or pick up the water or lava. In both tests, the observer fired both on the initial placement of the liquid and on the next "flow tick"*** for lack of a better phrase. I don't have redstone connected to the observer, it fires directly into a piston.
: Just a phrase I came up with representing the amount of in-game ticks it takes for a liquid to flow. The amount of time it takes in ticks for a liquid to go 1 block is a "flow tick"