The ghost of Betty Dukes still haunts the aisles of Walmart Inc.—and the halls of Walmart’s legal department, which is having to deal with the latest round of gender discrimination lawsuits.

Dukes, the former Walmart worker who died last July, led 1.5 million women into a class action lawsuit on gender discrimination in 2001, only to see the U.S. Supreme Court toss it on a technical ruling over procedure, not on the merits, in 2011.