Error in console "Refused to apply style from..etc"

Hi,
After the theme updates that happened about a week ago, I started noticing that the following error appears in the browser console.
Just wondring if this is theme related and how to fix it?

(index):1 Refused to apply style from 'https://coptic-treasures.com/wp-content/themes/generatepress/rtl.css?ver=5.5.1' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.

I use a child theme which calls up the main theme's rlt css file. However, I see now that the main theme does not have a css file called "rtl.css".
So what shall I do?

Here is the code in the child theme's function.php file:

function generatepress_child_enqueue_scripts() {
	if ( is_rtl() ) {
		wp_enqueue_style( 'generatepress-rtl', trailingslashit( get_template_directory_uri() ) . 'rtl.css' );
		
	}
}
add_action( 'wp_enqueue_scripts', 'generatepress_child_enqueue_scripts', 100 );

a sample post that you can check:
https://coptic-treasures.com/book/38-shepherd-accourding-to-my-heart/

thanks in advance.