This needs to be more specific. For instance: lava does not turn into cobblestone when water is poured on flowing_lava[level=2]. This will also stop the flow of water since the game intends for water to create cobblestone when it's on lava before moving again.
This does not duplicate MC-4641 because that report is talking about the end of a lava stream (where lava should not move anymore) not making cobblestone. The issue in MC-146152 is that pouring water directly onto the same lava level (2) won't create cobblestone either.
This needs to be more specific. For instance: lava does not turn into cobblestone when water is poured on flowing_lava[level=2]. This will also stop the flow of water since the game intends for water to create cobblestone when it's on lava before moving again.
Confirmed for 19w12b and 1.13.2.