according to OP-9664 I am submitting a request for adding info on help site about how NP calculates the Date and Time fields when you use it in a dynamic name. I think it is better to explicitly state this information..
The official help site page https://help.qlik.com/en-US/nprinting/June2020/Content/NPrinting/ReportsDevelopment/Dynamic-report-n... doesn't mention how the files Date and Time are calculated. I suggest to add this information on the help site.
Qlik Technical Support