Creating new Calculated Table DAX FIRSTDATE has duplicate dates. That is not supported

[mshaffer]

Trying to create a calulated table that summarizes the dates by incidentID but keeping getting error of duplicate dates passed to FIRSTDATE even when I use the DISTINCT Function on those dates.  Not sure what is causing it as I can't debug the DAX statement at all 

[v-caliao-msft]

@mshaffer,

I have tested it on my local environment, we cannot reproduce this issue.
Table = ADDCOLUMNS(SUMMARIZE(Table1,Table1[Type]),"FirstDate",FIRSTDATE(DISTINCT(Table1[Date])))

Please provide us some sample data, so that we can try to reproduce this issue and make further analysis.

Regards,

Charlie Liao

[mshaffer · Accepted solution]

Resolved my issue through another route.  Made arelationship bi-directional and then used the FIRSTNONBLANK function to grab the acknowledge date.  Then mapped the AcknowledgeDate, MitigatedDate, and ResolvedDate to my table with a single status per incident.

Here is the DAX expression I used. Admittedly  I'm still a novice at using DAX expressions so I may still not be doing the most efficent method but it's working.

AcknowledgeDate1 = FIRSTNONBLANK('ArgusDevTeam ICM (All Status Changes)'[AcknowledgeDate], [AcknowledgeDate])