Polygon Heimdall V2 Outage May Have Caused Temporary Network Disruptions, Bor Layer Remained Operational

Key Points

1. Heimdall V2 faced a one-hour downtime on July 9, 2025, caused by a consensus bug, while the Bor layer continued operating normally.

2. The Bor layer operates independently from Heimdall V2, handling block production and transaction execution without interruption.

3. The Heimdall V2 upgrade introduced significant technical complexity, including CometBFT and Cosmos-SDK v0.50, described as Polygon's most complex hard fork since 2020.

4. Post-downtime, Polygon identified synchronization inconsistencies across RPC providers' Bor nodes and is working to resolve them.

5. Heimdall V2 is the consensus client for Polygon’s proof-of-stake chain, while the Bor layer focuses on block production and transaction execution.