Moving Average - Visual Level Filters Applied

Instead of one table you should have at least two.

Create a Date table. Link it to your Referral table.
Try the following measure after the above steps.

MovingAverage2MonthAllRefs = CALCULATE (
    AVERAGEX ( Referrals, Referrals[Total] ),
    DATESINPERIOD (
        Dates[Date],
        LASTDATE ( Dates[Date]),
        -2,
        MONTH
    )
)

I changed the columns in the DatesPeriod function.