WebEngine does not save cookies on Qt 5.13.0

I am building up on the quicknanobrowser example, I have the following profile:

property QtObject defaultProfile: WebEngineProfile

{ storageName: "Profile" persistentCookiesPolicy: WebEngineProfile.ForcePersistentCookies  }

I have seen that there is no Cookie reference in my file system except the ones that are created with 5.10.1.

The same code creates and uses /home/myuser/.local/share/MyProject/my-project/QtWebEngine with Qt 5.10.1, but cookies are neither saved nor used in Qt 5.13.0. Is it a Qt bug or do I need to add something extra to enable this in Qt 5.13.0?
Thanks