Quantum exposed: this address has revealed its public key in a prior spend. A sufficiently powerful quantum computer could derive the private key.
pubkey 0421668e2e87aecf383599fbacdb254272ee0bb3b7bb37a544eaa662c0bc9f5848ddffbeb3c65ecc80051e03427b42bcf7957b419641a8cdd317ecd87236ccdde8