Created attachment 151103 [details]
A pivot table based on two close datetimes (1 s difference)
Opening the attached spreadsheet, and re-saving as XLSX, then opening in Excel, produces warning about "found a problem with some content", then "Removed Feature: PivotTable report from /xl/pivotTables/pivotTable1.xml part (PivotTable view); Removed Records: Workbook properties from /xl/workbook.xml part (Workbook)". The pivot table is dropped (replaces with static content).
Since commit https://git.libreoffice.org/core/+/baed960b8ce55370a040d0c0f49bd3fdc16bdf84.
Not a regression: the said commit introduced saving datetime fields to pivot tables; previous to that, such fields weren't stored properly at all (implementation defect).
Mike Kaganski committed a patch related to this issue.
It has been pushed to "master":
tdf#125055: properly round fractions of seconds
It will be available in 6.3.0.
The patch should be included in the daily builds available at
https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.