Yes, and awareness lags reality by years. Walmart's third-party marketplace opened the door to the same seller networks that work Amazon, and those sellers face less scrutiny there because fewer brands are watching. A first scan for an established brand almost always turns up live knockoffs.
Most brand protection habits were built on Amazon: Brand Registry, Report Infringement, the whole routine. Walmart's brand portal has its own process and evidence rules, and teams that are busy on Amazon simply never set it up. The result is a channel where the same fakes sell untouched.
Complaints go through Walmart's brand portal with platform-specific evidence requirements. Filings formatted to those rules move; generic complaints stall. As on every platform, removal is only half the job, because sellers pushed off Walmart re-list or relocate to Amazon or TikTok Shop.
Run one scan of Walmart Marketplace against your catalog before doing anything else. Most brands find enough live counterfeits in that first pass to make the priority obvious.