Sui mainnet was halted three times over 48 hours last week after an upgrade introduced a rare edge case in the chain’s gas-charging logic, the Sui Foundation said in a post‑mortem published Sunday. The outages — clustered across May 28–29 — were all linked to a new feature shipped in the v1.72 release, and each fix either triggered or exposed the next failure. What went wrong - The first outage began at roughly 7:00 a.m. PT on Thursday and lasted nearly seven hours. A newly introduced address-balance feature created an uncommon interaction with Sui’s existing coin objects. When a transaction was canceled for insufficient funds, an underflow error caused validators to crash because the gas-charging routine still attempted to charge the same funds. - To visualize the issue: Sui balances aren’t a single number but a stack of coin objects — like holding banknotes of 60, 30 and 10 SUI instead of one 100-SUI bill. The chain combines these “notes” when paying. The bug emerged only in a narrow scenario where the new address-balance flow and traditional coin objects mixed during gas payment and cancellation. How the team responded The core team brought mainnet back up around 1:30 p.m. PT with an interim fix that addressed the most common manifestation of the bug but carried “a known issue with a low probability of causing a halt.” The team accepted that risk to restore service quickly while developing a more comprehensive patch. The cascade continues That low-probability condition materialized the next morning. A second outage began at about 5:00 a.m. PT on Friday when a transaction triggered a masked variant of the same bug: an insufficient-funds error was overridden by another cancellation reason, bypassing the interim patch. A more robust fix was completed and rolled out by roughly 9:40 a.m. PT. The third halt was a knock-on effect. When validators restarted to install the robust fix, participation in the protocol that bootstraps Sui’s on-chain randomness fell below the required threshold and randomness disabled itself as designed. A latent bug prevented that disabled state from being persisted to disk, so validators were unaware randomness had been turned off on the next restart. The next epoch change then stalled for close to six hours as randomness-dependent transactions — such as lotteries, certain games, and some NFT mints — piled up in a paused queue. Impact and context - No user funds were at risk during any of the outages, and no committed transactions were reverted, the foundation said. - The SUI token dropped roughly 8% during the incident cascade to a low of $0.90 and was trading near $0.90 on Monday — about a 19% decline for the week, per CoinDesk data. - These events mark Sui’s third major reliability incident since its 2023 mainnet launch, following a two-hour transaction-scheduling bug in November 2024 and a six-hour consensus divergence in January 2026. The Sui Foundation’s post‑mortem lays out the chain of technical failures and the remediation steps taken. The incidents underscore how subtle interactions between recently deployed features and legacy behavior can cascade into multi-stage outages on complex Layer‑1 systems. Read more AI-generated news on: undefined/news