A/C clutch engaging when Defrost is turned on?

[rvnwlf]

While in the process of troubleshooting a vacuum problem I noticed something.

When turning the climate controls to either just window vent or window and floor vent (orange images) the A/C clutch will engage. Turning it to the 2 other vents (white images) it will turn off. It does turn back on when MAX is selected.

Is this normal?

[goldgp]

Ac will engage in defrost to dehumidify,it's normal.