I've experienced the same issue and extensively combed the html (view page source & expect element). The last time I worked on it was August 18th to get this function centered on the page in mobile - no problem there. Then I checked in on the page this week, August 24th and it's no longer there.
Please fix this.
The last known location was here with the breadcrumbs <nav class="ProductItem-nav">
Thanks to @Pointer for trying out a new trial site with no change. I was going to try that next - you saved me a step to debunking this error.
Like @Melian I also have the Product Navigation set to both