In Ancient City, had a makeshift brewing setup in a shulker to quickly get some Night Vision Potions.

Steps:

1. Created Solid block area (to eliminate duplicate bug for not being able to fill from waterlogged sources)

2. Dumped Water in 1 x 1 recess surrounded by solid block, in Redstone chamber under portal.

3. Tried to fill Water from it and it failed.

4. Repeated in other parts of City and still failed.

4. Left Ancient City and worked as intended.