Polygon's proof-of-stake network experienced a significant disruption on July 30, 2025, when a validator exiting the network triggered an unexpected bug in the Heimdall consensus layer. The incident lasted over an hour and caused delays in consensus finalization, though block production on the Bor execution layer continued uninterrupted.
According to Polygon Foundation and CEO Sandeep Nailwal, the issue originated from a recent technically complex upgrade to Heimdall (v0.2.16), which introduced vulnerabilities when validators exited. This caused Remote Procedure Call (RPC) nodes to fall out of sync, disrupting user access to decentralized applications. QuickNode reported stalled block production at height 74,592,238, while Polygonscan data showed blocks continuing with 2-second intervals.
Services were partially restored within hours, with the Foundation confirming full resolution by 11:01 UTC. The disruption follows Polygon's major July upgrade – its most complex to date – which aimed to accelerate transaction finalization. Network metrics show $1.2 billion in DeFi assets and $2.8 billion in stablecoins remain on-chain.
This marks Polygon's third significant outage since 2022, including a 10-hour zkEVM failure in 2024. Despite the incident, Nailwal emphasized this was a coordination gap rather than protocol failure, with POL tokens trading at $0.21 (down 2% post-outage).