These are two possibly separate bug reports.
In the following pictures unit and feature positions are encircled with a white line.
1) It seems features aren't always rendered when their base isn't visible in the screen. This applies for both the shadows and the model. An example below shows the difference between feature and unit rendering (unit properly has shadows even when the base isn't visible).




Here's a close up of that single feature:

And now if we move just to make its base slightly off the screen.


2) Using the same feature and unit, it seems features are rendered quite weird when they are zoomed out, while units still remain recognizable. That small mark is supposed to be the feature: