Hey I have try your fixees and it seem to work now, although I am not sure exactly what fix it.
Now the preview work on my pages, but not with my partials modules like my navigation menu. The preview seems to be activated, but the new saved changes to theses partials are not visible, again only in my prod environnement (preview mode in local work as expected - see screenshots).
So I talked with the team and it seems there is a small issue with Previewing content coming from the vuex store. They are aware of this and plan to work on it in the next week or 2.
So I'm not sure there's anything you can do to resolve this at the minute. I'm sorry for the inconvenience this has caused you in the time being.
To reproduce the bug, you can edit the document "menu", save it and hit the Netlify preview.
You will see that on the first load the preview is not working until you click on a link.
Maybe the problem is that the data is fetch from prismic before the preview mode is activated ?
Thanks for getting back to me on this. I'll have to find time to get a look at it, but I believe it's something to do with the store and preview mode as you suggested.
When I test preview in localhost, partials modification are showing, but not when I test on production environnement (nuxt static generate on netlify). Do you know if there is a workaround ?