Summery:

When you cast your fishing rod onto flowing water, the bobber will float like it is on a water source.

Recreation process:

1. Place a water source so the water flows across flat land.
2. Cast your fishing rod at the spot where the water ends
3. Watch to see bobber float to the top like it is a water source.

Thanks for your time

P.S. - please allow more items in your off-hand on Minecraft Bedrock Edition PS4.

-Josh (sorry for no picture or video)