Thank you @Andrew_Wathen_ Q: OK so the numbers for the same report change between refreshes? - not really going to be the overlap issue then.  A: If I refresh the same report for the same time period, numbers are the same. But if refresh with more days, the numbers changed.  Q: Can you confirm if an...

Yes, the numbers changed when I refreshed the report.  I also changed the date to a single date to minimize the overlapping situation but that seemed not help. (To confirm, to have a visit qualified in a segment, either the visit start date or end date should be in the data range, right?) 

Yes, the logic between these 2 containers are the same. The scroll button didn't go to the end but actually nothing is below it. 

I am creating 2 segments and expect these 2 segments yield the same number of visit, but I found segment B has higher visit. Why?  @Andrew_Wathen_  I read some your posts, and you seem like an expert for segmentation. Any chance you know why?