joose This is a flaw caused by the cache mechanism, which checks for "folder modified time" to see if a folder changes. Unfortunately, editing a text file does not change the parent folders modified time, and the existing folder cache may therefore remain valid, and the text file may contain outdated file size.
To maintain a strong cache mechanism, I didn't have any immediate solution for this, especially considering incorrect file size is non-critical. I will consider other options in the future, but it means using a slower mechanism to validate cache.
You could resolve this by setting config 'cache' => false,
although that will cause slower performance.