Ajaxized boxes returning "-1" after period of time

I’m using Ajaxize with WP Super Cache to ajaxize some custom wp_query functions. After a few hours, the ajaxed divs just show a “-1” where the content should be.

First, what does the “-1” mean?

I’m using WP Super Cache so I’m wondering if this happens once super cached files are generated. This is with WP Super Cache 1.4. I’m not using the dynamic content function, relying on Ajaxize to keep the content dynamic.

Second, how can I fix this?

Third, is there a way to change the “-1” to a custom message? E.g.: “Nothing to display right now, please check again later.”

Thanks!

https://wordpress.org/plugins/ajaxize/