When using the Recommended Screen Resolution for the selected display, only Maintain Display Scaling will be visible. The Custom scaling option will also be available in order to correct overscan.
The remaining scaling options (Centered, Stretched, and Maintain Aspect Ratio) will be revealed when a screen resolution different than the maximum supported resolution or recommended for the selected display is selected.
Previous to build 1.100.2765.0, switching to Centered, Stretched, and Maintain Aspect Ratio when using the Recommended Screen Resolution would not make valid changes to the display, hence the scaling options were removed when the Recommended Screen Resolution is set.