CodeIgniter 4 base_url() bug

If I will add a file parameter to base_url() function, it will add an equal sign (=) to the end, which should not be there. I am considering this as a bug. I tested it in PHP 7.4 and 8.

The code

PHP Code:

echo base_url('favicon.ico' . '?' . 'v101'); 


will output

Code:

http://localhost/favicon.ico?v101=

I am using these parameters to force browsers to get the new versions of a files.