A fix for memory leaks in script-security released in version 1.60 (PR 253) inadvertently caused the inner caches in SandboxResolvingClassLoader.parentClassCache (which contain the actual cached classes) to always be weakly referenced, allowing them to always be cleared out by the garbage collector, since the inner caches are never strongly referenced anywhere else. In cases where the garbage collector is running frequently, this significantly reduces the effectiveness of the cache, and can contribute to performance problems in code that uses SandboxResolvingClassLoader, such as Pipeline.