Cache issue in Next JS 15 with App Router

[Gavrushuk]

Version Next JS: 15.5.2
Using App Router

Since we're using Next.js 15+, not all fetch requests are cached by default. Because of that, we explicitly added caching options:

For the posts list:

{ next: { tags: ["posts"] }, cache: "force-cache" }

For a single post:

{ next: { tags: [`post-${slug}`] }, cache: "force-cache" }

We also use a revalidation API endpoint where we trigger the following after a post is published, edited, or deleted:

revalidateTag("posts");
if (slug) {
  revalidateTag(`post-${slug}`);
}

The issue is that when a post is updated, the data is revalidated, but when navigating through our site—switching between pages such as the news feed (static), post page (dynamic), and home page (static)—we see inconsistent data.

On some pages, the post title is updated; on others, it still shows the old version. Sometimes the title on the single post page is outdated while the lists are already updated.

If we keep navigating between links, after about ~15 minutes, everything eventually syncs and shows fresh data. Additionally, if we manually refresh a page twice, only then does it display the updated content.

We're trying to decrease staleTime in the Next.js config from 5 minutes to 1 minute for static pages, but it hasn't helped.

Maybe someone has experienced this issue and successfully fixed it. Any suggestions or insights would be greatly appreciated.

Thank you!