When a Kendo UI ExpansionPanel is nested within another, and the initial expanded configuration is set to false, the panel will not open the first time it is attempted. When the widget is initialized, it searches for all expand icons in the expander's wrapping element, which in this case would include the icons of the inner expanders. Thus, when a user clicks on an outer one, you also affect the inner ones.
The Kendo UI ExpansionPanels do not open the first time clicked.
The inner expansionPanels should open as expected.