This could be due to caching on your server. Caching allows your website to load faster, but it also means there is a delay for back-end changes to migrate to the front-end.
Try contacting your host’s tech support for options to clear the server cache.
Use a caching plugin?
You can try to temporarily disable the caching plugin to see the changes more quickly, or you can modify your caching settings to allow for more frequent clearing.