@yourshandyman
It looks like your problem is being caused by the WP Fastest Cache plugin that you are using on your website.
Cache plugins serve a static version of your page which makes the page load faster as it does not have to query the database. The problem here is that when the database is changed then the cache needs to be cleared, otherwise it will continue to serve the static page which will no longer contain the updated page content.
When a review is submitted, this adds a new review to the database. If the cache is not cleared when this happens, then your reviews page will not display the new reviews (until the cache is cleared again).
I am unsure how you have your reviews page set up. However, if you are displaying your reviews on the same page that you provide the review submission form, then the code in the link below should help solve this problem:
https://pastebin.com/C97n2RW4
If it does not, you will need to contact the authors of the caching plugin that you are using (which I assume is the “WP Fastest Cache” plugin) and ask them for assistance to configure the caching plugin settings correctly.