File attachment deleted prematurely if shared by two activities

I'm not sure when this happened but happens in 5.82 too.

1. Create an activity with two target contacts.
2. An option will appear below the With Contact field. Choose the option to make separate activities.
3. Add an attachment.
4. Save.
5. Edit one of the created activities and click the trash can icon to delete the attachment. The file/entity_file records are ok but the physical file has been deleted from the filesystem.
6. View the other created activity and try to download the file from it. You get an error because the file has been deleted.

Edit: It seems pretty old, but what's happening is it's not creating the file/entity_file records correctly in the first place. It's creating a duplicate file record but with the same file uri.