DataFlows with Group or Merge steps are not working correctly

[laura_gb]

We have 2 major issues with a dataflow that previously was working successfully to pull data from Project Online. 
Issue 1 - Failed Refresh
Last week a DataFlow stopped refreshing with the following error

After some investigation and testing different combinations we found that one of the Merge steps in the dataflow was the culprit. If we removed the step the dataflow would refresh.

Issue 2

When we connect to the dataflow from Power BI any entities that include a Group or Merge steps are not available.

[laura_gb]

Changed the datatype of the columns being used for the merge from Date to DateTime and the dataflow will now refresh.

If I change all the date columns in all the entities to datetime they all now come through to Power BI.

[v-qiuyu-msft]

Hi @laura_gb, 

The same issue has been reported internally: CRI 159107800. ETA for fix is end of week.

Best Regards,
Qiuyun Yu

[PereBosch]

I have exactly the same issue with merged entities!.

Best regards,

Pete

[laura_gb]

@PereBosch  was your merge using some date columns?

If it was change the type of those columns to DateTime and that was the work around to get mine up and running again.

L

[PereBosch]

Sorry Laura, do yo mean I need to change all entities/table columns in each table within a dataflow as DateTime? Or just the columns of the entities/tables I'm not able to see?.

I guess you'll have the same warning I have: when changing some columns to DateTime some of the fields are showing error messages before saving/closing the entity...

[PereBosch]

I tried your recomendation and I'm now able to see the table after changing all columns as DateTime and connect to the 'missing table. Unfortunately when I connect to the Dataflow all columns show error messages and changing DataType to the original one doesn't solve the problem. Do you have the same issue?

Best Regards,

Pete