posts carousel displays two rows instead of one

Post carousels: All five of our service items suddenly get displayed in two rows on the homepage, rather than scrolling through four items at a time in one row (see klantmaatschap.nl).

Is this a known bug, or did we mess up something? – And how can we fix it?

Please Help!

p.s. current code:
[posts_carousel heading="Featured Services" post_type="services" order_by="order" order="ASC" limit="10" meta="no" excerpt="yes" excerpt_char_limit="72" exclude_current="no" width="four columns" scroll_by="4"][/posts_carousel]