Hi,
Any errors in the Event log? Do other type of changes do show up right away?
Have, and if so how have, you configerd the use of Web Farms? As some of the Caching might not be pushed to the other node if you haven't enabled or configured it correctly?
https://docs.kentico.com/k82/configuring-kentico/optimizing-website-performance/setting-up-web-farms/configuring-web-farm-servers
If all is set up check if there are any Web Farm tasks blocked or giving an error!