Some Plutus scripts in the witness set or in an output are invalid. Scripts must be well-formed flat-encoded Plutus scripts, CBOR-encoded. Yes, there's a double binary encoding. The outer-most encoding is therefore just a plain CBOR bytestring. Note that some tools such as the cardano-cli triple encode scripts for some reasons, resulting in a double outer-most CBOR encoding. Make sure that your script are correctly encoded. The field 'data.malformedScripts' lists the hash digests of all the problematic scripts.