Dialog action buttons have a float: right on them which flips their order, which means it shows Agree on the left and Disagree on the right. This goes against material guidelines for modal actions, which says that "Dismissive actions are always placed directly to the left of affirmative actions." This issue appears in the materialize documentation as well.
Go to http://materializecss.com/modals.html and click on either/both modal.
Or here's a live example http://codepen.io/codypearce/pen/LxVaZP