Well you are successfully launching the Itv Hub from the Youview box
Then you are seeing the Itv hub menus and programmes and making your selection.
You are receiving the first set of adverts from the ITV Hub
so that suggests that the Youview box is correctly launching the ITV Hub and is able to display what the ITV Hub service is providing it. Clearly you are not receiving the main programme content . that suggests to me either the ITV Hub advert stream is either not completing successfully or the main content is not starting.
i believe in the Youview ITV Hub , There is Settings option on the top row and then a About Tab which gives the version number of the ITV Hub and there is Reset button.
Might be worth trying,
There are occasional threads on the Youview community about similar experiences including one recently.