Position absolute does not work in IOS

I'm trying to align a button at the end of a ion-item My css button is:

position: absolute !important;
right: 0%;
bottom: 0;

and the result on Android is:

But in% w / o%, the button simply does not appear, or appears in some items in the middle of IOS , sometimes above, but does not appear as in Android.

  

Is there a problem with ion-item to position: absolute ?   Am I doing something wrong?   Is there a better way to position a button at the end of the ion-item?

Using IOS it consumes the entire area of the button, leaving no space above for the texts. Thanks for any help =)