The Alpha Illusion: Reported Alpha from LLM Trading Agents Should Not Be Treated as Deployment Evidence. - Yuxuan Ye; Jun Han; Ao Hu; Juncheng Bu; Yiyi Chen; Liangjian Wen; Danilo Mandic; Danny Dongning Sun; Xu Yinghui; Zenglin Xu (CoRR, 2026)