The abundance of miss translation from the Japanese into English is rather astounding. A company like SE shouldn't have these issues.

RDM Dualcast Tool Tip

効果時間中にオートアタックかアビリティ以外のアクションを実行すると、連続魔は即座に解除される。
Effect is canceled upon auto-attack or execution of any action other than a spell.

The English says it cancels on Auto-Attack but the Japanese clearly states that is cancels on any action OTHER than an Auto-Attack or Ability.