When working in the shaded (up to Vectorworks 2021 OpenGL) render style, there is a limit of 8 light sources that visibly emit light per drawing. The light of all other light sources will not be calculated. With “Renderworks” fast or extended Renderworks Styles such as “Interior Fast” all light sources will be calculated, as well as their reflection.
Some symbols such as cooker hoods and light fixtures also contain light sources. These are included in the limit of 8 light sources per drawing.
The visualization palette allows you to find a list of the number and type of light sources. To do this, go to Window/Palettes/Visualization Palette.