Escaping the Echo Trap: On Credit Assignment Failure in Multi-turn LLM Self-Reflection. - Linxuan Du; Guangquan Xue; Xiaobo Liang; Qipeng Huang; Yuyang Ding; Xinyu Shi 005; Zhang Yijun; Ji Qi; Wenpeng Zhu; Juntao Li 005; Min Zhang 005 (ACL (1), 2026)