Measures: Getting Around Conflicting Filters and Table Relations

As I think has been stated, the problem is that the relationship between the date dimension the the Action_Date needs to be ignored. I learned that this can be done using the function USERELATIONSHIP(), in which you explicitely define the relationship you want used.

My new formula reads:

EventCount = CALCULATE(COUNT('Event'[EMPLID])
    , USERELATIONSHIP('Event'[CURRENT_HIRE_DATE]
        , 'Calendar'[DIM_DATE]
        )
    )

And it correctly returns, what at the time of the original postings would have been, 370 for October of 2018 AND has the bars (yellow) in the correct time periods on the chart:

Thanks for really sticking with the hard questions, Microsoft...