A bug was discovered in the Tezos mainnet a week after its official launch. According to tzscan.io, on September 24, the block release time increased from 1 to 20 minutes due to the vulnerability.
The project’s developers fixed the problem in a short period of time, and on September 25, morning, the Tezos mainnet started working normally.
Tezos (XTZ) is a new decentralized blockchain that governs itself by establishing a true digital commonwealth. Tezos mainnet was launched on September 17.
https://coinstelegram.com/2018/09/25/bug-was-discovered-in-tezos-xtz-mainnet/