TLDR
- Polygon implemented a hard fork to address a bug that caused a 15-minute delay in transaction finality.
- The bug affected parts of the network, causing disruptions to validators and RPC services.
- Polygon’s engineers rolled out emergency updates, which restored normal network operations.
- The faulty milestone proposal was identified as the root cause of the finality delay.
- Polygon successfully completed the hard fork, ensuring milestones and checkpoints resumed processing normally.
Polygon has restored full network stability after addressing a bug that delayed transaction finality by 15 minutes. The issue disrupted parts of the Polygon ecosystem, affecting validators and RPC services. Polygon engineers rolled out emergency updates to resolve the bug, which caused certain nodes to halt. The network now operates normally with finality processing restored across the ecosystem.
Polygon’s Network Faces Temporary Disruption Due to Faulty Milestone
The issue began early Wednesday, affecting Polygon’s Bor block producer and Erigon data access layer. A faulty milestone proposal caused disruptions, halting some Remote Procedure Call (RPC) services and validators. While the blockchain continued producing blocks, the faulty milestone delayed local finality. This left parts of the network struggling to process fast, deterministic finality.
According to Polygon’s team, the bug occurred under certain node configurations. Engineers quickly identified the problem and took steps to fix it.
“Restarting affected nodes resolved the issue for several validators and RPC providers,” Polygon’s team said.
UPDATE:
The hard fork has been successfully completed, and milestones are now processing normally along with state sync. Checkpoints are going through and consensus finalization has been fully restored on Polygon PoS.
We will continue to monitor the network closely to ensure… https://t.co/UwiAYdcKXu
— Polygon Foundation (@0xPolygonFdn) September 10, 2025
The problem became more apparent when Polygonscan, the network’s block explorer, showed no updates for over five hours. Polygon later clarified that Polygonscan’s nodes had stopped after a faulty milestone was generated by Heimdall, the project’s consensus engine. To address the situation, Polygon switched to operational nodes and ensured that block production remained active.
Polygon Resolves Bug with Hard Fork Update
To resolve the finality issue, Polygon deployed a hard fork at 3 p.m. UTC, introducing Bor version 2.2.11-beta2 and Heimdall version 0.3.1. The hard fork purged the faulty milestone, ensuring that milestones and checkpoints finalized normally. Polygon confirmed the upgrade was successful and that transaction finality had returned to normal across the network.
“Milestones are now processing normally along with state sync, and checkpoints are going through,” the team announced.
Polygon’s network has now resumed full operations with all systems functioning as expected. The hard fork was necessary to correct the faulty milestone and restore the finality process, which had been disrupted.
Sandeep Nailwal, Polygon’s co-founder, explained the cause of the disruption.
“The root cause came from a faulty milestone proposal that pushed some Bor nodes onto divergent forks,” Nailwal said.
Despite this, he emphasized that checkpoint finality on Ethereum had remained intact.
Earlier today, Polygon PoS experienced a disruption where checkpoint finality on Ethereum was still active, but local fast finality on the chain (i.e. milestones) were delayed.
For context: milestones are a lightweight alternative to checkpoints, enabling faster, deterministic… https://t.co/ulINLtlurV
— Sandeep | CEO, Polygon Foundation (※,※) (@sandeepnailwal) September 10, 2025
Polygon engineers continue to monitor the network to ensure no further issues arise. The team is also investigating the origins of the faulty milestone to prevent similar disruptions in the future.
Network Reliability Remains a Concern Amidst Growing Pains
This disruption adds to ongoing concerns about Polygon’s reliability, especially after its recent Heimdall v2 upgrade. While Polygon has made several improvements, such as reducing finality times, network stability remains a critical issue. Despite the efforts, the total value locked (TVL) on Polygon has decreased significantly, dropping from a peak of $9.43 billion in 2021 to just $1.2 billion today.
The incident comes just weeks after the Bhilai hard fork, which increased throughput to 1,000 transactions per second. While these upgrades aim to improve the network’s reliability, this event highlights potential vulnerabilities. Polygon’s native token, POL, has fallen by 30% this year, reflecting investor concerns over the chain’s performance.
