When "Vibrant Visuals" is enabled in the video settings, strange broken black lines appear when looking underwater — especially near glass blocks or air domes. The artifacts look like jagged diagonal lines or grid patterns, and they only appear when this feature is turned on.
This issue does not occur when Vibrant Visuals is turned off.
The GPU and monitor are functioning normally in all other games and applications.
The problem is purely visual and tied to the in-game rendering system.
This issue is being tracked at MCPE-220439.