Ionic 4 Refresher

Has anyone else had issues with the refresher not responding to swipes unless you are at the very top of the page. So for example if i slightly scroll down then try to pull, it just stops the scroll at the top and doesn’t let me overscroll to trigger the refresh.

I have written an ionScroll function to shrink the header on scroll but that shouldn’t affect it surely?

<ion-content [scrollEvents]="true" #myContent (ion-scroll)="scrollHandler($event)">
    <ion-refresher slot="fixed" (ionRefresh)="doRefresh($event)" margin-top>