The beta anomaly, whereby low-beta stocks outperform high-beta stocks on a risk-adjusted basis, remains a persistent challenge to the Capital Asset Pricing Model. A recent study by Cao et al. (2025) links this pattern in U.S. equities to a state-dependent leverage-constraint channel, in which subdued ambiguity and risk aversion during low uncertainty periods push constrained investors toward high-beta stocks, inflating their prices and depressing subsequent returns. We test whether this conditional mechanism extends to the G10 economies. After confirming the original U.S. result over a longer horizon, we partition each international market into high-and low-uncertainty regimes using the global EPU index over 1997-2025. Across most G10 markets, the negative relationship between market beta and CAPM alpha weakens or disappears during high-uncertainty periods, but becomes significantly more pronounced when uncertainty is low. The pattern survives alternative specifications of the global index, country-level EPU measures, and different beta estimation methods.