When using map reports either directly from the report or using the dashboard, when attempting to scroll vertically after zooming in the report you will notice that nothing happens but the user is still allowed to scroll horizontally.
1. Create a report of the map type.
2. Select the maping data to use location (easy to reproduce when using the task table).
3. Run the report.
4. Click the '+' icon to zoom into the report.
5. Click and hold and move to the sides to scroll horizontally.
6. Now click and hold and move up and down to attempt to move vertically, Notice how nothing happens
Please be informed that this issue is now fixed in the Rome version.
Unfortunately no workaround is in place for the lower versions.