Hi Bernd,
Thank you for contacting Syncfusion support.
We have checked the sample in the Github https://github.com/kaaax0815/Weather.Xamarin/archive/v1.1.zip and we have modified the sample and added scrollview as SfPullToRefresh pullable content now vertical scrolling, horizontal scrolling and PullToRefresh is also working. We have also attached the tested sample and video for your reference.
Please check the sample and revert us if you need any further assistance on this.
Regards,
Pradeep Kumar B