ed25519 - failing wycheproof testvectors

[karel-m]

While hacking on DCIT/perl-CryptX#59 I have found out that our current implementation of ed25519_verify falsely validates/verifies the following signatures which should be rejected:

{
  "tcId" : 63,
  "comment" : "checking malleability ",
  "msg" : "54657374",
  "sig" : "7c38e026f29e14aabd059a0f2db8b0cd783040609a8be684db12f82a27774ab067654bce3832c2d76f8f6f5dafc08d9339d4eef676573336a5c51eb6f946b31d",
  "result" : "invalid",
  "flags" : [ "SignatureMalleability" ]
},
{
  "tcId" : 64,
  "comment" : "checking malleability ",
  "msg" : "54657374",
  "sig" : "7c38e026f29e14aabd059a0f2db8b0cd783040609a8be684db12f82a27774ab05439412b5395d42f462c67008eba6ca839d4eef676573336a5c51eb6f946b32d",
  "result" : "invalid",
  "flags" : [ "SignatureMalleability" ]
},
{
  "tcId" : 65,
  "comment" : "checking malleability ",
  "msg" : "54657374",
  "sig" : "7c38e026f29e14aabd059a0f2db8b0cd783040609a8be684db12f82a27774ab02ee12ce5875bf9dff26556464bae2ad239d4eef676573336a5c51eb6f946b34d",
  "result" : "invalid",
  "flags" : [ "SignatureMalleability" ]
},
{
  "tcId" : 66,
  "comment" : "checking malleability ",
  "msg" : "54657374",
  "sig" : "7c38e026f29e14aabd059a0f2db8b0cd783040609a8be684db12f82a27774ab0e2300459f1e742404cd934d2c595a6253ad4eef676573336a5c51eb6f946b38d",
  "result" : "invalid",
  "flags" : [ "SignatureMalleability" ]
},

The key:

"key" : {
  "curve" : "edwards25519",
  "keySize" : 255,
  "pk" : "7d4d0e7f6153a69b6242b522abbee685fda4420f8834b108c3bdae369ef549fa",
  "sk" : "add4bb8103785baf9ac534258e8aaf65f5f1adb5ef5f3df19bb80ab989c4d64b",
  "type" : "EDDSAKeyPair"
},
"keyDer" : "302a300506032b65700321007d4d0e7f6153a69b6242b522abbee685fda4420f8834b108c3bdae369ef549fa",
"keyPem" : "-----BEGIN PUBLIC KEY-----\nMCowBQYDK2VwAyEAfU0Of2FTpptiQrUiq77mhf2kQg+INLEIw72uNp71Sfo=\n-----END PUBLIC KEY-----\n",