QComboBos is larger than it should be when used as editor of a view on macOS

Reproducer attached. It is a modified version of "Spin Box Delegate Example" with QSpinBox replaced by QComboBox. The original example of QSpinBox looks alright. But QComboBox does not - it looks larger than it should be. And consequently, a small part of it on top is "clipped out" of the cell. Qt Creator shows the same issue. See the attached screenshot. Notice that how those QComboBox is slightly "clipped out" on top.

Also, the issue is not reproducible on Windows. Seems like a macOS thing.