@amblender, try reducing extra vertices. I was seeing the same thing that you are experiencing. Here is how I resolved it. From the board example below, I had six rows of loops and six columns of loops. After putting in my cracks and dings, I Dissolved any extra vertices. Especially for a low poly project, I view this step as housekeeping. I probably have more of this type of clean up on all my objects. Hopefully this helps.