As long as there isn’t any technical issue on your site, such as plugin incompatibility or another glitch, the most common reason for your changes not appearing on the site is cache.
You may have cache on the site, the server, a CDN or intermediate cache.
Try to hard-refresh or disable cache plugins temporarily.
If that doesn’t seem to be the issue, more information is needed to troubleshoot or a link to the site to take a look, together with an example of a post that behaves as you say.
Do your new posts get published at all? If not, it might be php limitations that give you problems.