It seems Wolfram Alpha appropriately excludes March 11th for the math folks (e.g. kind of like SQL BETWEEN, syntax convenience, etc) and Bard appropriately includes January 11th and March 11th, as that is how it would be commonly interpreted.

Edit: or not, March 11th is not a weekday. Though I count 43 weekdays including Jan 11th, so perhaps Wolfram is using an open interval while bard is using a closed interval.