The 65-year-old star was pictured without a face covering, and is said to have walked out without making a purchase.
Last year, it was revealed Bruce had been quarantining in Idaho with ex-wife Demi Moore and their daughters Rumer, 32, Scout, 29, and Tallulah, 26.
Originally, his current wife Emma and their two daughters Mabel, 8, and Evelyn, 6, had been staying in Los Angeles, but in late May the model was able to travel to Idaho with her children to meet up with the rest of the family.
Scout had revealed in April that Emma and Bruce weren't quarantining together because one of their kids had stepped on a hypodermic needle discarded in a park so had needed medical tests.
She explained: "My stepmom was supposed to come up here with my little sisters, but my younger sister, who is now about to be [six] years old, at a park, had never gotten the talk about not f****** with hypodermic needles that she found.
"So she actually tried to poke her shoe with it and poked her foot ... My stepmom had to be in LA waiting to get the results from taking her to the doctor.
"So my dad came up here and then travel got crazy so my stepmom stayed in LA with my little sisters."