Page with Content Fragment List on Dispatcher's cache is not updated after new content fragment published

Our client's on-prem AEM application has 1 author instance, 1 publish instance, and 1 dispatcher, all running on the same EC2 server.

There is a published page containing a content fragment list component. When I create a new content fragment and publish it, the page's HTML and model.json on the publish instance get updated immediately. On the dispatcher's cache, the page's HTML gets updated, but in the page's model.json the new content fragment still does not exist, even after a long time. 

Currently in the cache invalidation setting of the dispatcher's configuration, both "*.html" and "*.model.json" are set to allow auto-invalidation. 

What could be the cause of this problem and what configurations should I look into?