Additional nginx directives/Leverage browser caching are ignored for WordPress website

Symptoms

1. Additional nginx directives/Leverage browser caching are set under Domains > example.com > Apache & nginx Settings for a WordPress website.
   For example:

   CONFIG_TEXT: location ~* .(js|jpg|jpeg|gif|png|css|tgz|gz|rar|bz2|doc|pdf|ppt|tar|wav|bmp|rtf|swf|ico|flv|txt|woff|woff2|svg)$ {
   expires 30d;
   add_header Pragma "public";
   add_header Cache-Control "public";
   }

2. Expiration headers are not applied 

3. The website has Hotlink protection security measure enabled at Domains > example.com > WordPress > Security.

4. curl utility shows that HTTP headers set in Additional nginx directives are not configured for files with extensions like .jpg, .png, .css, etc.

   # curl -I -c - "https://example.com/path-to-file.jpg" -k
   HTTP/2 200
   server: nginx
   date: Fri, 21 Dec 2018 10:41:47 GMT
   content-type: image/jpeg
   content-length: 173018
   last-modified: Wed, 19 Dec 2018 16:36:53 GMT
   etag: "5c1a73a5-2a3da"
   x-powered-by: PleskLin
   accept-ranges: bytes

Cause

Resolution

Install WordPress Toolkit updates.