Summary:
Non-updated water sources can be generated in the world. It is possible to renew the water source only if it is swamped or removed and then placed.

It seems to happen randomly 1 time in a chunk on the border of a chunk in water 1 block deep.

Seed: -1251937210
Coords: 1968 62 11872
Coords: 1944 62 11888
Coords: 1968 62 11888
Coords: 1890 62 11904
Coords: 1888 62 11920

Steps to reproduce:

1. Create a world with the specified seed.
2. Move to the specified coordinates.
3. Make sure the level below is made up of hollow blocks to prevent water from flowing (under the non-updated block).
4. Break the blocks under the non-updated block (block of water at the specified coordinates).
5. Watch the water.

Observed results:
The water block will not update when updating adjacent blocks. 

Expected results:
The block of water must be refreshed when update adjacent blocks.

Video:
Minecraft 2021-12-16 11-01-02.mp4

Image: