Causes of stale cache

Hello:

I’m trying to gain an understanding of the various causes of a stale object cache. In particular I’m trying to understand what WordPress plugin developers might inadvertently do to cause an object cache such as redis to not clear an option even after the option has been updated.

I’m asking because I’ve seen a number of plugins that update options but the option in the redis cache isn’t getting cleared/refreshed. Only when the cache is manually cleared does the plugins’ operations respect the new option value.

Thanks.