Results disappear when refreshing or clicking back

Hey,
The form works great, you can see it working by clicking “search” on here: https://hbocr.tstwebdesign.co.uk/

The only problem I’m having is when you search and it displays the results, if you click refresh the results disappear. Also, if you click on the listing and go back, it disappears.

I’d really appreciate your help.

https://www.ads-software.com/plugins/advanced-custom-post-search/