Grounding or Guessing? Visual Signals for Detecting Hallucinations in Sign Language Translation - HAMIDULLAH, Yasser; Dutta Chowdhury, Koel; Al Ghussin, Yusser; Yazdani, Shakib; Oguz, Cennet; Genabith, Josef; España-Bonet, Cristina (International Conference on Learning Representations, 2026)