Hey, @powerrelaxs! Thanks for reaching out about this.
Please take a look at this forum post from back in March, which addresses the same inquiry by a few others in the Community.
But, basically what it says is that ?nopreview is showing on your end only, and can be tested by navigating to your storefront using an Incognito browser. If you would prefer to no longer see it though, please clear the cache on your browser.
Let me know if you have any other questions or concerns.