Count TRUEs in filtered expression

This is a simple idea, but I can't figure out how to do it.  
I only need three columns in a table:   

object_id (int key), 
event_month (date), 
event_condition (logical)

Even if condition is FALSE, there may be a date.  

I just want to get the maximum count of conditioned objects based on date.  

Monthly_Max = MAXX( 
    KEEPFILTERS(VALUES([event_month])), 
    COUNTX(FILTER('Table', [event_condition] = TRUE()), 
        [object_id]))
)

But the second filter, doesn't respect the first filter.  
And I have tried other ways with CALCULATE with no success.  

I feel like this is gonna be easy, but I still need to get my head around it.  
Thanks