Mondelez International (NASDAQ:MDLZ) is taking Aldi to courtand not over pricing, but packaging. In a federal lawsuit filed this week in Illinois, the snack giant claims Aldi's store-brand cookies and crackers are riding too closely on the coattails of its flagship products. Think Aldi's chocolate sandwich cookies in Oreo-blue wrappers or its Thin Wheat crackers dressed in gold like Wheat Thins. Mondelez says it's not a coincidenceand it's had enough.

The company argues that Aldi's packaging could confuse shoppers and dilute the brand equity Mondelez has spent decades building. While Aldi has previously tweaked or pulled some lookalike designs after being contacted, Mondelez alleges several copycat packages remain on shelves. The lawsuit also names other productslike knockoffs of Nutter Butter, Ritz, and Premium crackersas part of a broader pattern that could, if unchecked, damage long-term brand value. Mondelez is asking the court to stop sales of these items and is also seeking financial damages.

This legal push comes as Aldi continues its breakneck expansion across the U.S., now operating more than 2,500 stores and naming a new U.S. CEO set to take the reins in September. But with similar lawsuits already handed down in the U.K. and Australiaboth siding against Aldiinvestors might start asking whether these packaging clashes are isolated incidents or signs of mounting brand risk for a retailer that's built its empire by borrowing familiar cues.

This article first appeared on GuruFocus.