The Sui Foundation has released a detailed post-mortem explaining the three network outages that disrupted the blockchain over a 48-hour period, revealing that developers knowingly deployed an interim fix with a recognized risk of causing another halt. While the decision helped restore the network faster, the exact failure scenario engineers anticipated occurred the following day, leading to yet another outage and raising new questions about risk management on one of crypto’s fastest-growing Layer-1 networks.
Three Outages Traced Back to a Single Software Upgrade
According to Sui’s investigation, all three outages originated from bugs introduced in the network’s v1.72 software release, which included a new address balances feature designed to simplify transactions and support gasless stablecoin transfers. The update created unexpected interactions with Sui’s gas-charging system that ultimately caused validators to crash and block production to stop.
The first outage began on May 28 and lasted more than six hours. Developers discovered that when two transactions attempted to spend the same address balance simultaneously, a canceled transaction could still trigger a gas charge. This created a negative balance error that crashed validator settlement processes across the network.
The Interim Fix Carried a Known Risk
Perhaps the most significant revelation from the post-mortem was Sui’s admission that the emergency patch deployed after the first outage was not a complete solution. The core team acknowledged that the fix carried a low-probability risk of triggering another network halt, but chose to deploy it anyway to restore the blockchain as quickly as possible while engineers worked on a more permanent solution.
According to the Foundation, the interim patch bypassed certain gas-processing steps when transactions failed due to insufficient funds. However, developers knew there were edge cases where other transaction errors could override the insufficient-funds condition, allowing the original bug to reappear. That exact scenario occurred on May 29, causing a second outage that lasted several hours. The disclosure is notable because blockchain projects rarely admit to deploying fixes that carry known operational risks. Sui’s report openly states that the team accepted the possibility of another halt in exchange for a faster network recovery.
A Third Outage Came From a Completely Different Bug
After engineers deployed a more comprehensive fix for the gas-charging issue, Sui experienced a third outage later that same day. Unlike the first two incidents, this disruption was tied to a separate bug involving the network’s randomness protocol and validator restart process during an epoch transition.
Sui validators use a distributed key generation system to create the randomness required for certain onchain applications. When validators restarted after installing the new software patch, a latent bug prevented the network from properly preserving randomness state information across restarts. As a result, transactions requiring randomness became stuck, causing the network to freeze again until validators coordinated another recovery effort. The third outage lasted several hours before developers implemented an emergency mechanism that allowed validators to force-close the stalled epoch and restore normal operations.
No Funds Were Lost, But Reliability Questions Remain
Sui emphasized that no user funds were ever at risk during any of the outages and that no confirmed transactions were rolled back once the network resumed processing blocks. The chain simply stopped accepting new transactions during each downtime window.
However, the repeated disruptions have intensified concerns about the network’s reliability. The incidents mark Sui’s third major outage event since launch and come at a time when the blockchain is actively competing with networks like Solana, Aptos, and Avalanche for developers, institutional users, and DeFi activity. The SUI token has also felt the impact. Following the outages, the token fell sharply and remained down double digits on the week as investors reacted to the growing pattern of upgrade-related disruptions.
Sui Plans Additional Safeguards
In its report, the Foundation acknowledged that parts of its gas-charging infrastructure have become increasingly complex and require stronger testing procedures. The team said it plans to improve failure containment systems so that future bugs can be isolated to individual transactions rather than bringing down the entire network. Sui also highlighted plans to strengthen end-of-epoch recovery mechanisms and expand the use of AI-assisted diagnostics that reportedly helped engineers identify the root causes during the outages.
