404-errors in security log

Hi,

The plugin seems to work fine, but the log of my iThemes Security plugin shows some 404-errors that apparently are related to WP Fastest Cache. There are 2 types:
/wp-content/cache/wpfc-minified/[zzz]/[xxx]index.js
/wp-content/cache/wpfc-minified/[zzz]/[xxx]index.css

(the [zzz] stands for 32 digits, the [xxx] 10 digits).

I have no clue what this means, but as it is an IP address from China and my site is purely regional, I suspect that it’s not an innocent visitor. Could you please let me know if anything can be done about it (apart from blocking this particular IP address)?

https://wordpress.org/plugins/wp-fastest-cache/