Collection-repeat overflow-scroll="true" does not work

Hi,
i got a very long list of elment to display and i appreciate how collection-repeat works but i got an issue with native scrolling + mouse wheel i had solved time ago by overflow-scroll=“true”: now on firefox/windows i scrolls very slowly again.

This is related specifically to collection-repeat: switching to ng-repeat on firefox i can see the native scrollbar and everything works fine but as soon i switch back to collection-repeat here again.

Here the live example:
https://culturaturismo.piemonte.firstlife.org/#/app/maps?c=45.08806600338162:7.966461181640626:9&date=2017-07-28T11:40:02.778Z&unit=hour&embed=viewer
click on the left side menu

ionic 3.6

Thanks for any support