When matrix projects are built, the final build status is set to "Not Built" if one of the configurations has not been built.

This is not the best strategy for it prevents to check the results for the configurations that have ran;  also, skipping some configurations may be a deliberate choice...

 Suggested improvement for the matrix build status computation,:

1. discard the configurations whose status is "Not Built", proceed with the remaining ones
2. a) if there are none, the matrix build status is "Not Built"
3. b) If there are some, proceed with these with the current computation strategy.