The claim is reasonably supported by corroborating evidence, but not cleanly proven from a fetched primary source in this run. The fetched PANews article 'Circle在Solana链上再次铸造5亿枚USDC，年内累计铸造380亿枚 | PANews' reports a confirmed 500 million USDC mint on Solana and explicitly attributes it to Onchain Lens. Separately, X search returned 'https://x.com/SolanaFloor/status/2044283178811089169', which states Circle minted about 750 million USDC on Solana in the last 24 hours. These are compatible: multiple mint events within a day could sum to roughly 750 million. However, because direct fetches of the X posts failed and no independently fetched on-chain explorer page was available, the evidence base is still partly indirect. That makes the claim likely true rather than confirmed with high confidence.