Softmax weights used implicit tau=1, producing near-uniform weights
when Q-gap=0.06: exp(0.06)≈1.06 → weights [0.35, 0.33, 0.32].
The mixture averaged all distributions → zero gradient to differentiate
actions → Q-gap frozen → val_Sharpe locked at 0.00 after epoch 19.
Now uses tau = max(Q_gap/3, 0.001). With Q-gap=0.06 and tau=0.02:
exp(0.06/0.02) = exp(3) ≈ 20:1 weight ratio between best and worst.
The 0.001 floor means even tiny Q-differences produce sharp weights,
preventing the uniform-averaging fixed point.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
c55d9d0276