Bugfix parity report for MC-70848 (mark as relates to), although the issue's manifestation differs slightly. I searched, but there didn't seem to be any tickets on the matter.

The bug

Much like the still fluid issue detailed in MCPE-152995, flowing liquids will also try to connect diagonally to other liquids. If a particularly low fluid tries to connect to a particularly high source, this will make the connected region appear to flow upwards, which is purely visual but highly misleading (and ugly).

How to reproduce

1. Recreate the setup shown in the screenshots, such that a water flow ends at a dedicated container region
2. Place water in that region such that it flows downwards diagonally to the fluod
3. Note that the thin fluid tries to connect upwards to the fluid it can't actually contact

Expected results

As no physical contact is made, the shapes would not try to link up.

Actual results

They do anyway.

Further notes

The same difference between this and Java Edition pre-1.18.2 listed in MCPE-152995 can be noted - fluids connecting diagonally to something above them does not happen. The connecting fluids still need to be on the same Y level, which makes this bug less common, but it still absolutely does exist and yields very similar effects.