When tightly-knit communities suddenly show electoral volatility, does it signal weakening group identity, or something else entirely? This question matters wherever cohesive groups vote as blocs: evangelical churches, immigrant enclaves, ethnic minorities, religious denominations. Conventional wisdom interprets such shifts as boundary erosion. This paper demonstrates the opposite.I exploit a natural experiment, Israel’s 2020 - 21 electoral crisis, to track voter transitions within ultra-Orthodox communities, where ethnically distinct subgroups (Ashkenazi and Sephardic) maintain near-total political separation despite shared religious practice. Using ecological inference on ballot-box data from five population centers across six elections (2019 - 2022), I document exceptionally high baseline party loyalty (90 - 95%), a dramatic disruption during the March 2020 – March 2021 transition when switching surged to 12 - 19%, and a return to high loyalty to the “new” party. a pattern that remained invisible in country-level aggregates and became detectable only through the ecological-inference framework applied here, and a return to high loyalty to the post-switch party..The synchronized switch of voting loyalty across geographically dispersed cities, occurring without residential mobility, suggests coordinated elite guidance rather than emerging voter independence. Paradoxically, mass switching demonstrates stronger, not weaker, institutional control.This finding exposes a methodological trap. Researchers sometimes use voting patterns as proxies for residential segregation, including in my own earlier work. When voters switched parties without moving, standard indices falsely registered political shifts as spatial integration, a confound that threatens any study that conflates demographic and political boundaries.The broader implication challenges how we interpret electoral behavior in cohesive communities worldwide: apparent volatility may signal disciplined coordination, and what looks like boundary erosion may actually reveal institutional strength operating through collective action.