Bug with output buffering

Hello,
Within your function brand_shortcode you have a bug. Within a conditional statement e.g. if ( is_array( $brands ) && ! empty( $brands ) ) {
you start the output buffering. At the end of the function, you use the ob_get_clean() to return the buffer content.
Now, the problem is, if the conditional is not fulfilled, it will not start the buffering, but still use the ob_get_clean() which will break any other code using its own output buffering.
You can replicate the issue while using WP Hide plugin. When viewing a WooCommerce Product, none of the URLs replacements occurs, as you hijack the other plugin buffering callback.

Thanks