We exported a SubSite using
Export-SPWeb with IncludeUserSecurity and versions.
Subsequently we imported the export to the root of a newly created SiteCollection on the same WebApp (SharePoint 2016).
When we did this in our environment, all groups and users are intact, but on our client environment all groups are empty at the new SPSite/Web.
Besides that, when listing the groups via PowerShell, we notice that some groups are missing from the SPWeb, though they are part of the groups at the SPSite. Meaning the groups were imported, but not added to the SPWeb for some reason.
Anyone have any idea why this is happening?