Quotes being escaped inside wp_editor when saved with wp_kses_post

WordPress always escapes quotes encountered in the super globals variables. It is
done in https://developer.wordpress.org/reference/functions/wp_magic_quotes/

You will most likely want to strip it with stripslashes before saving it into the DB. something like

update_option( 'tld_wcdpue_settings_email_content', wp_kses_post( stripslashes($_POST['tld_wcdpue_settings_wpeditor'] ) ));