Swimming mode

What happened: Swimming mode activated when sprint jumping into 1 tall water sources

What I expected: After sprint jumping into 1 tall water source, I expected the player to be standing in water

Steps to reproduce:

1. dig 1 block pool (any dimension; 1x1, 1x2, 1x3, etc.)
2. fill with water
3. sprint towards water pool
4. jump into pool while sprinting
5. player enters swimming mode