Yeah the new site consistently showed results that either violated your query (e.g. returning fare classes outside of what you explicitly specified), had multiple options that were completely missing relative to old matrix, or would drop the specific flight you picked on the first leg after selecting the second leg (yes!).

Sad to see another tool bite the dust (I still remember the matrix iOS app which was great for doing quick and dirty searches for flights that was faster than anything at the time or since). End of an era.