No conflict displayed when trying to request creation twice

Reproduction steps:

• Request creation of a new page Foo.Test with content "This is a test"
• Request a second time the creation of Foo.Test, this time with content "Something very different" and save the changes in the previously created change request

Expected result:

• the modal displays a conflict error and the save does not happen

Obtained result:

• there's no error, the new version is saved in same change request, overriding previous changes, and still has a version "filechange-1.1"