The way the Spurs lost their last two games, to the Pelicans and the Mavericks, probably felt familiar. It's not hard to draw parallels to the two defeats at the hands of the Bucks and Suns from earlier this month: San Antonio’s offense slowed down in the second half on each occasion, while opponents had little trouble scoring.
The defensive issues are concerning, but largely have to do with poor communication on defense, as Gregg Popovich and Manu Ginobili mentioned after the Dallas game.