Nothing wrong with this and Kudos!
In MOST cases, nesting is perfectly legal. In this case, during your stay in DEN "plans" arose and you were required to return to LAX?!? It is hidden city ticketing that most folks refer to which would be LAX-DEN-MSP (ex.) and jumping off in DEN.
I am contemplating a similar "run" in the next few weeks, were I just go back and forth for a few days (family in both cities) and get that pesky requalification over with
With the promo and Plat bonus, it is pretty nice not having to go coast to coast.