TechShareShare this articleCopy linkX (Twitter)LinkedInFacebookEmailSui Mainnet Faces Three Halts in 48 Hours Due to Upgrade Bug

The Sui Foundation's analysis released on Sunday links all three outages to issues arising from a new address-balance feature introduced in the v1.72 update, which interacted poorly with the blockchain's gas and consensus mechanisms.

By Shaurya Malwa|Edited by Sam ReynoldsUpdated Jun 1, 2026, 6:02 a.m. Published Jun 1, 2026, 5:38 a.m. 3 min readMake preferred on

Key Points:

  • The Sui mainnet experienced three disruptions on May 28 and 29, triggered by a new feature in the v1.72 release that uncovered a flaw in the blockchain's gas-charging system, according to a post-mortem from the Sui Foundation.
  • The first two outages were caused by bugs related to how mixed gas payments were processed when transactions did not have enough funds, while the third outage was due to a hidden bug associated with the on-chain randomness protocol during validator restarts.
  • Although there were no losses of user funds or transaction reversals, the SUI token's value decreased by approximately 19% over the week, marking the network's third significant reliability issue since its mainnet launch in 2023.

The recent v1.72 update introduced a feature that revealed a flaw in the Layer-1 blockchain's gas-charging logic, which led to three separate mainnet halts on May 28 and 29. Each resolution either initiated or uncovered the next failure, according to the Sui Foundation's post-mortem published Sunday.

The initial outage commenced around 7 a.m. PT on Thursday and persisted for nearly seven hours.

The foundation indicated that this incident originated from an unusual issue in the way the network managed gas for transactions that were using both the new address-balance feature and traditional coin objects. The bug resulted in validators crashing due to an underflow error when a transaction was canceled due to insufficient funds, yet the gas routine still attempted to utilize those funds.

In this context, a coin object can be likened to a digital banknote. Instead of having a single SUI balance, a user's holdings consist of several distinct "notes" that can be moved or combined. For instance, a wallet might contain three coin objects valued at 60, 30, and 10 SUI, rather than a single 100-SUI balance. When making a payment, the network combines the necessary notes.

Validators are the entities that operate the network by processing transactions, validating them, and maintaining the blockchain.

The core development team managed to restore the network around 1:30 p.m. PT using what they termed an "interim fix" that addressed the most frequent bug version, albeit with "a known issue with a low probability of causing another halt." They accepted this risk to expedite the restoration of the mainnet while a more comprehensive fix was created.

This known risk manifested itself the following morning. A second outage initiated around 5 a.m. PT on Friday when a transaction triggered a variant of the same bug, where the insufficient-funds error was overridden by a different cancellation reason, circumventing the interim patch. The core team implemented a more robust fix, which validators adopted by approximately 9:40 a.m. PT.

The third halt emerged as a consequence of the second outage. Upon restarting to implement the robust fix, validator participation in the protocol responsible for generating the network's on-chain randomness fell below the necessary threshold, leading to the disabling of randomness as intended.

(On-chain randomness is essential for generating unpredictable numbers that all validators must agree upon, critical for applications that rely on chance, such as lotteries and certain games.)

A hidden bug then failed to save this disabled state, leaving validators unaware that randomness had been turned off during the next restart. As a result, the next epoch change was stalled for nearly six hours, with randomness-dependent transactions accumulating in a paused queue.

The foundation confirmed that no user funds were jeopardized during any of the outages, and all committed transactions remained intact.

The SUI token experienced a decline of about 8% during this series of incidents, reaching a low of $0.90 and trading near that value on Monday, resulting in a weekly drop of approximately 19%, based on data from CoinDesk.

This series of events marks the third significant reliability failure for Sui since its mainnet launch in 2023, following a two-hour transaction scheduling bug in November 2024 and a six-hour consensus divergence in January 2026.