diff --git a/crates/ml/src/trainers/dqn/fused_training.rs b/crates/ml/src/trainers/dqn/fused_training.rs
index b9cd644ce..eedebd90b 100644
--- a/crates/ml/src/trainers/dqn/fused_training.rs
+++ b/crates/ml/src/trainers/dqn/fused_training.rs
@@ -614,7 +614,7 @@ impl FusedTrainingCtx {
             popart_enabled: hyperparams.popart_enabled,
             hindsight_fraction: hyperparams.hindsight_fraction,
             curriculum_enabled: hyperparams.curriculum_enabled,
-            gradient_stage_diagnostics: std::env::var("FOXHUNT_GRAD_DIAG").is_ok(),
+            gradient_stage_diagnostics: true, // DIAG: force ungraphed path to isolate CUDA Graph issues
         })
     }