Cycles in picker view

Hi everyone, I just finished my first app and I have a doubt about whether picker view automatically makes a series of loops in its func. I put some prints inside the funcs and this is the result only when starting the view with the picker:

Every time I select it the cycles continue. It's normal? Is there a way to avoid or control it?

Thanks in advance for any response.

Cycles in picker view
 
 
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