Expand/collapse issue when grouping + filtering

By following these steps on Tutorial 401, you can see a disconnect between rendered rows and the collapse/expand all icon:

• Group rows by Age using the column header menu
• Use the expand all icon to expand all rows
• Search the Name for xyz and see all rows filtered out (hidden)
• Clear that search and see all rows rendered again in a collapsed state
• Note that the expand all icon is actually in a collapse all state

I would expect one of two scenarios:

• When clearing xyz, all rows would be rendered again in their previous expanded/collapsed state
• The collapse all icon would be properly displayed as an expand all icon

Based on my application requirements, I would must prefer that rows are rendered again in their previous state.