Sui Foundation Explains Why the Mainnet Stopped Three Times in Two Days

Key Highlights

• The Sui mainnet suffered three separate outages between May 28 and May 29, 2026
• The first two incidents were linked to bugs introduced in the network’s v1.72 upgrade
• A temporary fix deployed after the first outage carried a known low-probability risk of causing another halt
• The third outage was triggered by a separate bug involving validator randomness-state preservation during restarts
• No user funds were lost or placed at risk during any of the incidents
• No previously confirmed transactions were reversed when the network resumed operation
• The Sui Foundation says all known issues have now been addressed and network activity has returned to normal

The Sui Foundation has published a detailed explanation of the three mainnet outages that affected the Sui blockchain over a two-day period, attributing the disruptions to multiple software bugs that emerged following the rollout of version 1.72. According to the foundation, the incidents were not caused by a single failure but rather by a chain of interconnected issues involving new network functionality and subsequent fixes.

The first two outages were traced to bugs involving Sui’s newly introduced address balances feature and its interaction with gas-charging logic. The v1.72 upgrade allowed users to store funds in address balances and pay transaction fees without relying exclusively on coin objects. However, under specific conditions involving transaction failures and gas processing, an unexpected software bug caused validator crashes and halted block production.

Following the initial outage, developers deployed an emergency patch to restore network functionality as quickly as possible. The foundation later acknowledged that this interim fix contained a known issue that carried a small probability of causing another halt. The team accepted that risk in order to bring the network back online while a more comprehensive solution was being developed. Unfortunately, the network later encountered the edge case associated with that temporary fix, resulting in the second outage.

The third incident occurred during a scheduled epoch transition after validators restarted to install the latest patch. According to the foundation, a separate latent bug involving the preservation of randomness state across validator restarts was unexpectedly triggered. This issue was unrelated to the original gas-charging bug but caused another network halt during the upgrade process.

The foundation emphasized that despite the disruptions, no user funds were ever at risk and the blockchain did not roll back any confirmed transactions. Once validators coordinated upgrades and implemented fixes, the network resumed normal operation without requiring transaction reversals or state resets.

The outages attracted considerable attention because Sui markets itself as a high-performance Layer 1 blockchain designed for decentralized finance, gaming, and large-scale applications. Repeated outages naturally raise questions about reliability, particularly as blockchain networks compete on uptime, scalability, and institutional readiness.

In its post-mortem, the Sui Foundation stated that validators have now fully addressed both the gas-charging bug and the randomness-state issue. The organization also indicated that lessons learned from the incident will be incorporated into future testing and deployment procedures to reduce the likelihood of similar failures occurring again.

While the network has returned to normal operation, the event serves as a reminder that even advanced blockchain systems can encounter unexpected software interactions when introducing new functionality. For developers, validators, and investors, the incident highlights the ongoing challenge of balancing rapid innovation with network stability and reliability.