Investors have a lot to chew on.Chipotle Mexican Grill (CMG 2.12%) has long been one of the most popular fast-casual restaurant chains around, but this year, the company has been struggling to bring in the same type of customer traffic to its restaurants that it's used to.After not seeing a same-store sales decline since 2020, which was early during the COVID-19 pandemic when people were staying home and businesses were shuttered, the company just reported its second straight quarter of comparable-store-sal ...