Running total measure works in one dataset but not another

Based on suggestions from these forums, I was able to create a running total measure:

Mitigation Risks = CALCULATE (
    SUM ( 'Sheet1 (2)'[Mitigated Risks]),
    FILTER (
        ALL ( 'Sheet1 (2)'[Creation Date] ),
        'Sheet1 (2)'[Creation Date] <= MAX ( 'Sheet1 (2)'[Creation Date] )
    )
)

The data set for that measure looks like this

Control	Creation Date	Mitigated Risks
BC-CTS-00000001	8/30/2016	10
BC-SEC-00000001	8/30/2016	79
FI-AM-00000001	8/11/2016	3
FI-AP-00000001	8/18/2016	3
FI-GL-00000001	7/26/2016	1
FI-GL-00000002	7/26/2016	1
FI-GL-00000003	7/26/2016	1
FI-MD-00000001	8/15/2016	1
FI-MD-00000002	8/15/2016	2
FI-MD-00000003	8/15/2016	1
MM-IM-00000001	7/26/2016	1
MM-MD-00000001	8/23/2016	1
MM-MD-00000002	8/25/2016	1
MM-PUR-00000001	7/26/2016	1
MM-PUR-00000002	7/26/2016	1
MM-PUR-00000003	7/26/2016	1
MM-PUR-00000004	8/25/2016	4
PS-00000001	8/22/2016	2

and the resulting running total looks like this

But when I apply the same logic to a different data set, it's not working:

TTD Outages All = CALCULATE (
    SUM ( 'IT Outages'[Total Time]),
    FILTER (
        ALL ( 'IT Outages'[Date of Outage] ),
        'IT Outages'[Date of Outage] <= MAX ( 'IT Outages'[Date of Outage] )
    )
)

The data all appears to be the same data type between the sets.  What could I be missing?