Just had an odd occurrence where the water was still flowing, even after I removed all of the source blocks. I had to shut down the game and reopen for it to clear (which it did just after I stepped through the portal).
Something similar happened with me today but in the live server. I destroyed a wall underwater to replace it with glass. I replaced it and sealed the room but water remained in as source blocks and the only way i could remove them was to just fill them with other blocks. This was weird because while removing other sides of the wall and replacing them with glass, this didn’t happen.
James wasn’t on steam last night so I don’t think it was him.
It was odd that after I logged in again, the flowing water was still there, but then immediately acted as though the source blocks had just been removed, and dissipated.