Sui upgrade faults trigger reliability test

Sui’s mainnet disruptions over May 28 and May 29 have put renewed pressure on the Layer-1 blockchain’s engineering controls after three separate halts were traced to bugs connected with its v1.72 software release and the handling of gas payments, validator restarts and on-chain randomness.

The network has since returned to operation, but the episode has sharpened scrutiny of Sui’s upgrade process because the outages occurred in close succession and interrupted transaction processing across core settlement infrastructure. The Sui Foundation said user funds were not at risk and committed transactions were not reversed when the chain resumed activity.

The first outage began at about 7am Pacific Time on May 28 and ended around 1.30pm. A second halt began at about 5am on May 29 and ended around 8.30am. A third disruption started at about 1.30pm the same day and ended close to 7.20pm. Status updates later showed validator participation recovering, with the network marked resolved after participation by stake reached up to 93 per cent.

The initial fault arose after v1.72 introduced address balances, a feature designed to give users another way to hold funds and pay gas without relying only on coin objects. The problem appeared when transactions used a mix of address balances and coin objects for gas. Under a narrow set of conditions, a transaction cancelled for insufficient funds could still be processed by a gas-smashing routine, producing a negative balance delta and causing validator crashes.

Sui’s core team first deployed an interim fix to bring the network back while a fuller repair was prepared. That decision restored service more quickly but carried a known low-probability risk. The second outage followed when a related variant surfaced: the insufficient-funds error was masked by another cancellation reason, allowing the underflow issue to bypass the first patch.

The third disruption had a different immediate trigger. Validator restarts connected to the stronger fix exposed a latent bug in how randomness state was preserved across restarts. Randomness is used by applications that require unpredictable outputs, including certain gaming, lottery and NFT functions. When the next epoch change arrived, the affected state handling contributed to another halt.

The outages have landed at a sensitive time for Sui, which has marketed itself as a high-performance blockchain capable of parallel transaction execution and low-latency settlement. Its technical pitch has attracted developers building decentralised finance, gaming and consumer applications, but reliability is now a central concern for users and infrastructure partners that depend on predictable uptime.

Market reaction reflected that concern. SUI fell during the disruption window, with trading data showing a sharp decline as block production stalled and confidence weakened. The token was down by a wider margin over the week as traders assessed whether repeated halts could slow network adoption or raise the risk premium attached to Sui-based applications.

The incident also adds to a longer record of operational stress on the network. Sui had suffered a transaction scheduling-related halt in November 2024 and another prolonged disruption in January 2026 linked to validator consensus processing. While outages are not unique to Sui among high-throughput blockchains, repeated full-network interruptions can affect developer confidence, exchange monitoring, institutional custody assessment and the willingness of decentralised applications to depend on one settlement layer.

The foundation’s explanation indicates that the failures did not stem from a single consensus collapse but from the interaction of new accounting features with existing execution safeguards. That distinction matters because address-balance functionality is intended to make Sui easier to use, yet the bug showed how usability improvements can introduce edge cases in systems where gas accounting, conservation checks and validator determinism must align precisely.

For developers, the main issue is not only that a bug occurred, but that each stage of remediation created exposure to another failure mode. The interim patch restored activity, the stronger gas fix required validator coordination, and validator restarts then revealed the randomness-state problem. That sequence underscores the difficulty of upgrading live blockchain infrastructure where safety, speed and decentralised validator adoption must be balanced under market pressure.

Sui’s response now turns on whether it can translate the post-mortem into stricter testing, better simulation of mixed gas-payment cases, more conservative rollout gates and clearer procedures for validator upgrades. The project’s own analysis points to gas charging as an area that needs the same code-quality standard as core execution and consensus components, a recognition likely to shape future releases.