When does caching actually become a performance bottleneck?

weve all seen the benefits of caching faster reads reduced database load happier users but ive been thinking about scenarios where the cache itself or our caching strategy might be the thing slowing us down maybe its cache invalidation gone wild or a cache thats too large to be efficient or even just the overhead of checking the cache when have you seen caching turn from a solution into the problem what are the telltale signs and how did you fix it