This behavior is on purpose. See SC Supprot answere:
This is expected behavior to avoid confusion when someone submits or approves item in workflow working with “Shared Layout” as in this mode a user does not see the actual page, but only the part that is used by all item versions.
I.e. in this mode, you can’t be sure what you are pushing to the next workflow state.
Only “Final Layout” gives you a full picture of what you have.