all cached files are deleted on new posts

I installed the plugin and enabled mod_rewrite caching. Cached version of pages will be created and delivered in the future, speeding up the site.

But, on every new or updated post all(!) the files in the cache directory are deleted (with pre-cache enabled) or renamed to *.needs-rebuild (without pre-cache).
The “Clear all cache files…” option is disabled, of course.