Nginx try_files fails on first parameter and returns 404

Bear with me, this is a long one.

In the beginning I created a Nginx server to server static files for my company, and it worked great with the following config snippet for serving the files:

server {
  # bunch of ssl stuff
  root /path/to/files;

  location / {
    include cors_support;
    sendfile on;
    sendfile_max_chunk 1m;

    try_files $uri =404;
  }

Simple, clean and functional. Until I thought I would add another function to this server: storing our application builds and serving them to our QA team. Since the application files can be quite big, I added another storage volume just for the builds and thought I could get away with this with a simple change to the Nginx config as follows (only relevant portions shown):

server {
  # mostly the same
  root /new/path/to/builds;

  location / {
    #same as before
    try_files $uri @cdn_files;
  }

  location @cdn_files {
    #some cors and send_file settings
    root /path/to/files;
    try_files $uri =404;
  }
}

What I expected to happen according to documentation:

• request comes in for a file
• checks the first block for the file
• file found? yes=sends file no=redirect to named location
• named location -> file found? yes=sends file no=404 page

What actually happens:

• request comes in for a file
• checks the first block for the file
• file found? yes=sends file no=404 page

I have tried several different attempts at fixing this, including some insane "hail mary" attempts.

This produces the same result (404 page):

# ... irrelevant code
root /;
location / {
  # ... more irrelevant code
  try_files /new/path/to/builds/$uri /path/to/files/$uri =404;
}

This produces the same result (404 page):

# ...
root /new/path/to/builds;

location / {
  # ...
  try_files $uri @cdn_files;
}

location @cdn_files {
  # ...
  root /path/to/files;
  try_files $uri =403; #note that the page delivered is 404 and NOT 403
}

This produces a 404 as well:

# I removed the "root" directive from the server block for this test

location / {
  # ...
  root /new/path/to/builds;
  try_files $uri ../realitve/path/to/files/$uri =404;
}

A couple of other things to note:

• The error logs only show 1 attempt at locating the file at the first parameter of the try_files directive.
• If the file exists in the first parameter of the try_files directive the file is delivered
• I don't think its relative but just in case: OS is Ubuntu 16.04

Edit:

• Nginx version 1.21.0