Sui experienced three mainnet outages within less than 48 hours between May 28th and 29th, temporarily disrupting transaction processing and settlement. This incident exposed the public blockchain's shortcomings in isolating abnormal situations and caused short-term disruptions to applications and users within its ecosystem.

The initial failure stemmed from balance and gas processing.

The first outage was related to Sui's newly introduced address balance and hybrid Gas payment system. According to the official explanation, in rare cases, when two transactions simultaneously attempt to access the same funds, one of them should have been canceled due to insufficient funds. However, the canceled transaction continued to enter the Gas processing flow, ultimately resulting in an invalid negative balance at settlement.

The development team subsequently modified the logic to prevent transactions canceled due to insufficient balance from continuing to undergo relevant gas processing, and the mainnet was temporarily restored.

Edge situation triggers second stagnation

However, the initial fix did not fully cover all failure scenarios. Sui explained that transactions can be canceled for various reasons, and in some edge cases, insufficient balance errors can be masked by other cancellation reasons, causing the original protections to fail and the same type of underflow problem to reappear.

After addressing these overlapping failure scenarios, the developers released a more comprehensive patch in an attempt to stabilize network operations.

• There were three shutdowns between May 28th and 29th.
• The first two failures were related to abnormal settlement paths.
• The key to fixing this is preventing erroneous transactions from proceeding to subsequent steps.

The third shutdown originated from the DKG mechanism.

The third mainnet shutdown was not triggered by gas payments, but rather by the distributed key generation system (DKG). After the validators restarted, insufficient participation caused the DKG to fail, but the failure status was not correctly recorded.

This caused transactions that relied on randomness to get stuck, and the network was unable to complete the scheduled epoch switch. The developers later added a mechanism to safely end the stuck epoch and adjusted the DKG state consistency handling after restarting.

In his summary, Sui noted that the current system lacks a deeper layer of protection, making it unable to limit the impact of single-point failures to a smaller scope. This means that although the problem originates from a rare edge case, once triggered, its impact can still rapidly expand.

SUI prices fell, but open interest increased.

During the outage, the SUI price fell from $0.998 to $0.8783, a cumulative drop of over 15% in a week. Meanwhile, open interest data did not show any capital outflow; instead, it indicated that traders were still increasing their positions.

This typically means that the market did not experience large-scale liquidation due to volatility, and short-selling pressure has rebounded. For Sui, the more critical issue going forward is not whether a single patch works, but whether the mainnet can prevent similar problems from recurring in subsequent operations.