I am running a Screening Design of experiment to identify the key factors affecting the output variable. The DOE includes 7 factors. Out of which 6 factors have 2 levels and 1 factor has 3 level. JMP is suggesting the L18 Hunter design matrix. But if I review the design matrix two of the runs (15 & 17, 16 & 18 in attached picture) have the same factor settings. Can you suggest why this is the case?