Description

It doesn't seem like the cache is working correctly for me. Every time I reload the page, I see the timestamps of the cache files update.
This shouldn't be the case, or?

Steps to Reproduce

        $infoFeed = new SimplePie();
        $infoFeed->set_feed_url($infoFeeds);
        $infoFeed->set_cache_duration(600);
        $infoFeed->init();
        $infoFeed->handle_content_type();

Expected Behavior

Cache not updating every run.

Actual Behavior

Cache is updating on every run.

Possible Solutions

If you have already ideas how to solve the issue, add them here. (remove this section if not needed)

Environment

PHP 8.1
SimplePie 1.8.0