Grinding block parent to Interior Light loses components
If you grind a block that an Interior Light is "mounted on" without grinding the Interior Light first, you lose the components for the Interior Light.
For example, take one Light Armor Block (25 Steel Plate), and mount an Interior Light (2 Construction Components). Grind the Armor Block without touching the Interior Light and you will lose the 2 Construction Components (and the Interior Light disappears).
This bug has been around for a long time. :(