PPO was only checking for NaN losses every 10th epoch, allowing NaN
to propagate for up to 9 epochs and corrupt model weights before
detection. Now checks every mini-batch in both MLP and LSTM paths.
Delete three dead gradient clipping methods from DQN agent:
- compute_gradients_and_clip (never called, hardcoded max_norm=1.0)
- clip_gradients (returns error, deprecated)
- clip_gradients_map (computes clip factor but never applies it)
Active DQN training uses AdamOptimizer::backward_step_with_monitoring
which correctly delegates to gradient_utils::clip_grad_norm.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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