Hello, I’m using WordPress add-on "All-in-One Event Calendar" at Japanese.
Since the og:description was not displayed correctly in multibyte language, I looked up and found a description of “substr” in app/view/event/single.php.
$desc = substr( $desc, 0, 300 );
Can you change it as follows?
$desc = wp_trim_words( $desc, 150 );