Why do some listings not have corresponding history records?

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We have about 154 (Active, Closed, Inactive Office & Terminated) listing where we do not have any corresponding history records.

Some of these have matching EntryDate and ModifiedDate, while others have different EntryDate and ModifiedDate suggesting the listing has been modified 1 or more times.

Why do some listings not have corresponding history records?

I've forward a list of the listings in question.

Thanks