@Anonymous @WarrenBelz my understanding of Attachments in SharePoint Lists is that they aren't part of the version history. This means that if you attached a doc to a list then later decide to update it / save it as a newer version the old version is lost ie a copy isn't kept. This behaviour is specific to SP List and different to Libraries - this is what I've been told by our SharePoint Developer.
With this in mind maybe what's happening is that when an attachment is added it is creating a version JUST FOR THAT ATTACHMENT. Then, if a new version of this attachment is required SharePoint references that version and updates that version?
You could probably test this by adding an att. to a list, noting the modification date/time of the version, copying over the top of this att. then re-check the version Date/Time. My guess is the version's date/time will update but the version number won't.
As I say above, I'm not the expert here but just trying to troubleshoot a solution.
As an aside, and because of this versioning issue with List attachments, our SP Dev recently changed a captured signature from an attachment in a List to JSON code in a multiline of text column, just to maintain version history.
