Cannot scroll down a Grid with a mobile browser

Steps to reproduce

1. run attached example, it's a normal Grid with a scrollbar in a mobile browser
   or simulate a iPad with Chrome
2. scroll down the Grid

Actual result

The scrollbar is pulled back to the beginning position after scrolling down.
Please refer to attached video for reproducing.

Debug information

1. This issue happens since 7.0.4. The 7.0.3 doesn't have such issue.

Workaround

assign the height to the Grid, like height="500px" or vflex=1.