Hi,

Make sure that you don't use plugin to change number oder post.  I checked on our demo. I see it working fine. 

Please try  deactive plugin ( excrept plugin come from theme and try it again ) - If it work, let's enable each plugin to check what's plugin caused this issue.

If it doesn't work, let's send me your website management information ( admin url site, username and password )  in order for me to have access to know exact issue.

Best Regards,

PenciDesign