The test observed `mon.observe(0.0)` first but the monitor's initial
last_value is also 0.0, so the first observation didn't fire. Test
expected 2/3 but got 1/3.
Changed observe sequence to (1.0, 1.0, 1.5) mirroring grad_balancer's
correct pattern: first differs from initial 0.0 → fires, second matches
→ no fire, third differs → fires = 2/3.
No production code change.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>