Major non-fungible token (NFT) platform OpenSea has denied hack allegations, saying that yesterday’s issue was related to user interface (UI) design.

“This is not an exploit or a bug – it’s an issue that arises because of the nature of the blockchain,” the OpenSea spokesperson told Cryptonews.com.

OpenSea detailed that the issue arises when users create listings for their NFTs and then transfer the listed NFTs to a different wallet without canceling the listing. The platform added that listings do not automatically cancel and also cannot be canceled by OpenSea.

“OpenSea cannot cancel listings on behalf of users. Instead, users must cancel their own listings,” OpenSea said, adding that it is “working on a number of product improvements including a dashboard where they can easily see and cancel listings” to address the problem.