Hi  @PeterinUK 

Thank you for raising this topic on TP-Link community. 

Can you see the latest data on the APP? Please make sure both device firmaware and APP are updated. And try to export the file again. 

If the problem still exists, can you share the screenshots here so that we can help to check it? For example, the data showing in the APP and the data from the file. 

  @PeterinUK 

Thanks so much for sharing all the detailed info, this issue you are experiencing sounds unusual. To address the issue and try to fix it, we would like to have a specialist look into this further via email. Please check your mailbox later, and let us know if the issue is resolved. Thank you!