Cumulative Milestone Bar Chart does not display every week (if the Values are 0)

Hi, FSP1303 

Your current DAX formula is filtering for dates up to the maximum date found in your calender-sample table for the selected fiscal year. If no milestones are set or reached for a week, that week will not show any bars, and if the labels are set to auto, it might not display the week number either. 

Make sure your calender-sample table has a row for every week, even those without milestones. then modify your DAX to the following

NP_Milestones =
CALCULATE(
    IF(
        ISBLANK(COUNT(Tasks[NP_Milestone])), 
        0, 
        COUNT(Tasks[NP_Milestone])
    ),
    FILTER(
        ALL(Calendar_Simple),
        Calendar_Simple[FiscalYear] = SELECTEDVALUE(Calendar_Simple[FiscalYear])
        && Calendar_Simple[Date] <= MAX(Calendar_Simple[Date])
    )
)

Also, you might want to adjust your viz to show values that are 0. 

refer: Solved: bar chart suggestion to show zero values - Microsoft Fabric Community

Show items with no data in Power BI - Power BI | Microsoft Learn