<p>Policy feedback is often viewed as either reinforcing or undermining policy stability. However, it can arise in multiple ways simultaneously, creating mixed policy feedback with complex effects on policy stability. We examine how mixed policy feedback affects policy stability by developing a framework to identify within- and across-level feedbacks, and applying it to two cases of contested climate policy involving domestic carbon markets in Australia (2014–2025) and Canada (2015–2025). In Australia, a nascent baseline-and-credit scheme eventually became entrenched despite initial policy instability, while in Canada, a seemingly stable carbon pricing policy survived early conflict but was later partially reversed. By examining how multiple feedbacks arose and interacted within changing political contexts, we show how mixed policy feedback can affect policy stability, leading to potentially surprising outcomes. This implies a need to go beyond assessing the net effects of mixed policy feedback to consider complex interactions alongside exogenous developments.</p>