NextJS middleware called multiple times when accessing an ISR page

I have a NextJS application that hosts an ISR page that fetches data from Supabase. There's a middleware that records a page visit before rendering the page.

export async function middleware(
  request: NextRequest,
  fetchEvent: NextFetchEvent
) {
  console.log('request.nextUrl.pathname', request.nextUrl.pathname);
  if (request.nextUrl.pathname.split('/').length === 2) {
    return linkVisitMiddleware(request, fetchEvent);
  }
}

The issue the middleware is called 2 or 3 times (dont' know why these numbers fluctuate).

The above logging will print the following on the server:

request.nextUrl.pathname /slug
request.nextUrl.pathname /slug
request.nextUrl.pathname /slug

The weird thing, this happens only in production (next start). Locally (next serve), it runs once as expected.

I saw a couple of mentions about reactStrictMode, but that didn't help

Edit:

Tested on NextJS 13.1.1, 13.1.6 & 13.3.0

After hours of debugging, I found the culprit.

The ISR page is using the fallback strategy as {fallback: true} and because of this, it tries to request the HTML page, and if not available, it accesses the same route again to fetch the data.

To circumvent this, I found that NextJS employs headers to differentiate between the type of the request. Here's my solution:

import { linksMiddleware } from 'middleware/links';
import { NextFetchEvent, NextRequest, NextResponse } from 'next/server';

export async function middleware(
  request: NextRequest,
  fetchEvent: NextFetchEvent
) {
  // These methods are used when accessing locale routes, so we discard them
  if (request.method === 'OPTIONS' || request.method === 'HEAD') {
    return NextResponse.next();
  }

  //Capture URL locale (if any) and id. For example: /ar/random-id or /random-id
  const pathParams = request.nextUrl.pathname.split('/');

  if (pathParams.length === 2 && isDataRequest(request)) {
    // This means that we are accessing the entity homepage
    return linksMiddleware(request, fetchEvent, 'entity');
  }

  return NextResponse.next();
}

export const config = {
  matcher: [
    // This is to prevent the middleware from running on the API routes and during development
    '/((?!api|_next/static|_next/image|favicon.ico|favicon.svg).*)',
  ],
};

/**
 * Check if the request is a data request for cases of fallback pages
 * This header is absent in the initial request
 */
const isDataRequest = (request: NextRequest): boolean =>
  request.headers.get('x-nextjs-data') === '1' ||
  // The header is absent in development mode since there's no fallback logic (SSR-like)
  process.env.NODE_ENV === 'development';

Also I added a check for the HTTP method for the cases of locale routing excluding OPTIONS and HEAD.