Incorrect values when calculating range

In your current setup, when the data11[Initial Date] is blank, DATEDIFF returns a null value, which is not correctly handled in your Range calculation. The solution is to first check if data11[Initial Date] is blank before calculating the difference. If it's blank, you should directly assign "Blank" to the range. Otherwise, proceed with the date difference calculation.

Range = 
IF(
    ISBLANK(data11[Initial Date]), 
    "Blank",
    VAR Differnece = DATEDIFF(data11[Initial Date], TODAY(), DAY)
    RETURN
        IF(Differnece >= 0 && Differnece < 46, "0-45",
        IF(Differnece >= 46 && Differnece < 90, "46-90",
        IF(Differnece >= 90, ">90")))
)