The swimming speed is different when the character walks into the water and when the character jumps into the water.

[Oing]

In my project, I noticed a difference in swimming speed that more than doubled when the character walked into the water and jumped into the water. (faster when jumping in)
I reproduced this in the demo, and I noticed a slight difference in speed.
I attach a video to help you understand.
I made the console display the average speed of the character every 100 Fixedupdates.

Desktop_1.mp4

drive.google.com

 

[Justin]

My guess is that it has something to do with the Speed Change ability and when it starts/stops. I will let you know more after I look into it.