"My Draft" section does not contain node authored by current user

When the author is not the creator of the node, it does not appear in "My Drafts" tab.

Here is my use case :
- user1 creates a new node and set user2 as author of this node (user2 cannot create node of this type)
- user2 does not see this new node in his "My Drafts" section but it appears in the content overview page

When I check node access permissions (with devel), user1 has permission to "view" and "update".

When I check permissions for user1 and "Edit moderated content" it says that user1 should have "Revert content revisions" and "MyContentType: Edit any content".

But in my case, I don't want this user to be able to create or edit any content of this type but only the ones for which he's the author.

A workaround is to use the content overview page but I would prefer to stay with the workbench way...
Any ideas of how I can manage this?