You must update Bartender 4 to 4.1.49 if you have updated to macOS 12.4
Date Missing in menu bar
macOS 12.4 introduces a new setting, turned on by default to only show the date when there is room in the menu bar, this means the date is not visible when Bartender is running unless you turn this to “always” in System Preferences > Dock And Menu Bar > Clock.