During Pega 25.1.3 upgrade, JavaEERuleUpdateUtility fails with a StackOverflowError while expanding a serialized rule stream. The recursive stack contains deserializeLink, resolveReferenceProperty, expandToProperty, and repeated XML page/property serialization calls. The utility loses the processing context and reports Exception caught processing: null;therefore, the failing pzInsKey cannot be identified from the logs. Please verify whether this is a known defect in the 25.1.3 Java EE rule update utility and provide a hotfix or diagnostic patch that logs the rule key before deserialization.
This appears to be a low-level platform issue that will likely require assistance from Pega GCS. I recommend opening an incident to confirm whether this is a known defect in the 25.1.3 upgrade utilities and to determine if a hotfix or diagnostic patch is available. As a reference, you can review the 25.1.3 patch resolved issues - Pega Platform 25.1.3 Patch Resolved Issues | Support Center