Deleting SharePoint Sites / Office 365 Groups that contain records

Hi,

I did a bit of an experiment, using the Office 365 Advanced Data Governance features, and think I've found a bit of a flaw in the system.

I create two labels - 1 called 'Finance' and 1 called 'Finance - Record'.  Both labels applied a 7 year retention period with the 'Finance - Record' label also declaring the items as a record.  I then created an Office 365 Group to which these labels were published.  I created and labelled some content within the SharePoint Site associated with the Group.  

I then tried to delete the content I had created and, as expected, I got a message telling me that I couldn't delete because of the retention period.  I then tried to delete the Document Library that contained this content.  Again, as expected, I received a message telling me this wasn't possible.  I then went to Outlook and attempted to delete the Group.  I was, of course, expecting to receive an error message preventing this but, to my surprise, the Group deleted quite successfully.

I have subsequently waited for 2 days and used eDiscovery to attempt to locate these records that I seem to have very easily deleted.  Nothing can be found.  I've even used PowerShell to 'hard delete' the Groups since, for 30 days, they're hidden and can be recovered (not sure, then, why eDiscovery couldn't find the content?) but this didn't seem to trigger the content moving to some kind of preservation location.

Most odd.  Could someone please explain how this is supposed to work?  I looked at:  https://support.office.com/en-gb/article/overview-of-retention-policies-5e377752-700d-4870-9b6d-12bfc12d2423.  Unfortunately, the information there is not accurate so it hasn't helped.

Thanks!

Ady