The conduit block can be placed in flowing water and turns that flowing water into a source block even.
MC-129768
Conduit can be placed in flowing water, creating a new water source
Resolved
Fixed
6
(Unassigned)
Confirmed
conduit, flowing_water
Minecraft 18w20b, Minecraft 1.13-pre1, Minecraft 1.13-pre5
Minecraft 1.13-pre6
Retrieved
Still happening in 1.13-pre1