Shortcode parameter not working

Hello

On the main ads page I am using the following shortcode found from here: https://awpcp.com/forum/faq/valid-awpcp-shortcodes-3-x/

[AWPCPCLASSIFIEDSUI]
[AWPCPLATESTLISTINGS limit: 20]

The problem is with the bottom one. It only shows 10 listings even though I’ve set it to 20? Any ideas on how I can fix the please?

Thanks

https://www.ads-software.com/plugins/another-wordpress-classifieds-plugin/