Why does partial or full rebuild of an extract fix missing data problems

Summary:

We sometimes find that our extracts are missing records that should included. Running the UE and filter sql shows the data should be present.

The data is not present in the xml output delivery.

We have found that by deleting a child data group and re-creating the data group fixes the problem, also, exporting the extract build and re-importing fixes the problem.

I posted a question on a similar topic recently:

Has anyone else had this problem and found and alternative to rebuilding?

Thanks

David

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