During November 2025, Kucoll focused on backend stability work for the spring-projects/spring-security repository, addressing a critical bug in template expression handling. By correcting typos in the AnnotationTemplateExpressionDefaults class name and its associated creation method across both Java and Kotlin configurations, Kucoll restored the intended functionality for default template expressions. This targeted fix prevented potential runtime misconfigurations and improved the reliability of template handling within Spring Security. The work demonstrated careful attention to code quality, with clear, well-documented commits and proper sign-offs. Kucoll’s contributions reflected solid backend development skills and a methodical approach to maintaining robust Java and Kotlin codebases.