Hi,
This looks like a yet unknown bug, I was able to identify it on our test servers as well. I will make sure to resolve this in the upcoming release.
If you want, you can add temporary FTP access, and I will patch it for you.
Alternatively, you can do it by yourself as well:
(before you start, please make sure to heva a back-up, in case anything goes wrong)
1. Open up the wp-content\plugins\ajax-search-pro\includes\classes\search\class-asp-search-cpt.php file on your web server via FTP
2. Replace it’s contents with this
3. Save, and it should work