2D Top-Down game question -

What is the best way to switch sprite of my character from swimming to walking and vice versa.
I currently use box collision to switch my sprite, and when character step on it everything works correctly, until my character step on the copy of the first collision, then nothing happens.
After deleting one of the objects regardless of whether it is a copy or an original, the sprite changes correctly.

I will be grateful for any tips or a better way to change sprites.