On wave soldered multilayer boards lean solder joints were found at some chip components such as resistors and capacitors. It came out that the components were those lean joints were found were mounted at solderpads that contained a via hole. This via hole was near or at the position at which the component connection was present. Especially on such positions different amounts of solder can be found after the wave soldering process. Some joints look very lean, while other joints show a more common massive fillet.
The attached article reviews the question of how these differences can be explained.