When using a Flow within an QQC2 ScrollView, the ScrollView doesn't track the Flow's implicitHeight changes and calculates the contentHeight wrong. It is necessary to add a manual binding contentHeight: flow.implicitHeight to fix it.
Please refer to the attached sample.
You can clearly see in the console.log the values being calculated for the contentHeight resulting in being able to scroll way past the bottom of the Flow.
If you uncomment line no. 24, it will work fine.
It is a regression from 5.12.0