When Keepouts are given a height, they will cast a shadow for a given time of year. The default value is the winter solstice from 10am - 2pm local time. Any modules that are shaded during the time window will be removed. To allow modules to be placed in the shade, uncheck the "Keepout from shade" checkbox.
Why are my Keepouts not casting shade?
The shade shown in the designer for Keepouts and Field Segments is directly impacted by the time entered in the Keepout from shade checkbox window. For example, entering a Start time of 2:00AM and an End time of 3:01 AM will show no shading effect in the Designer, as the sun path is not present during that time. Entering a time window that is too short may also cause this result.