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<!-- Describe the issue -->

Starting with the following unsigned transaction:

```
cHNidP8BAHMCAAAAAXg6mTOjO3d9K0RiVOr87oYRYhYB/Bpomi66nXc85ebsAAAAAAD9////Avs+EQAAAAAAF6kU4lwd88Ejsg5sG0iVOiL2/c05MHKHoIYBAAAAAAAXqRSxG32ZtPml0iJQGDVxp82wjHBD+4cs7RUAAAEBIHZOFQAAAAAAF6kUP2yi0rx2ke1Lmdk5gsR+WIvukb+HAQQWABSL8jhHTVLizeYj0cS1ClE18i8jbCIGAnwLKYOB2pXhdmi+i21xj17Np67DQdv7RPiIVKqOrp++ENZSlGkAAACAAQAAgAAAAIAAAQAWABSLPsswJus4oRP6Zq1BmWcxI5hNQiICAgi7iTon5Hy59yU96uKT12AU4/bhxQy7CeEdkfg5sZLoENZSlGkAAACAAQAAgAEAAIAAAQAWABQ6Ram/bbw29IPN92ylIqYKhU1ThyICA3oH7xQc22oDM2dG6g/VZ05JLscr/hEQKUI4fTMKvUjRENZSlGkAAACAAAAAgAAAAIAA
```

I first call:

```
walletprocesspsbt "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" true ALL true
```

Which generates:

```
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
```

Which is "complete: true" and parses fine. But then if I run `walletprocesspsbt` on the result AGAIN (don't ask why ... or do, but this should be idempotent):

```
walletprocesspsbt "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" true ALL true
```

I get the following:

```
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
```

Which is still reported as "complete: true", but when I try to decode or finalize it:

```TX decode failed PSBT is not sane.: unspecified iostream_category error (code -22)```

I would expect `walletprocesspsbt [foo] true ALL true` to be idempotent, or at least produce output that's parseable.

This is all testnet and I have attached the wallet.dat in case it's useful (it only has two UTXOs and very few keys.).

I am going to continue trying to debug this, but I figured since I haven't gotten it yet I should document it. Please let me know if someone else starts looking into it.

"  \"ismine\" : true|false,        (boolean) If the address is yours or not\n"
            "  \"solvable\" : true|false,      (boolean) If the address is solvable by the wallet\n"
            "  \"iswatchonly\" : true|false,   (boolean) If the address is watchonly\n"
            "  \"isscript\" : true|false,      (boolean) If the key is a script\n"
            "  \"iswitness\" : true|false,     (boolean) If the address is a witness address\n"
            "  \"witness_version\" : version   (numeric, optional) The version number of the witness program\n"
            "  \"witness_program\" : \"hex\"     (string, optional) The hex value of the witness program\n"
            "  \"script\" : \"type\"             (string, optional) The output script type. Only if \"isscript\" is true and the redeemscript is known. Possible types: nonstandard, pubkey, pubkeyhash, scripthash, multisig, nulldata, witness_v0_keyhash, witness_v0_scripthash, witness_unknown\n"
            "  \"hex\" : \"hex\",                (string, optional) The redeemscript for the p2sh address\n"
            "  \"pubkeys\"                     (string, optional) Array of pubkeys associated with the known redeemscript (only if \"script\" is \"multisig\")\n"
            "    [\n"
            "      \"pubkey\"\n"
            "      ,...\n"
            "    ]\n"
            "  \"sigsrequired\" : xxxxx        (numeric, optional) Number of signatures required to spend multisig output (only if \"script\" is \"multisig\")\n"
            "  \"pubkey\" : \"publickeyhex\",    (string, optional) The hex value of the raw public key, for single-key addresses (possibly embedded in P2SH or P2WSH)\n"
            "  \"embedded\" : {...},           (object, optional) Information about the address embedded in P2SH or P2WSH, if relevant and known. It includes all getaddressinfo output fields for the embedded address, excluding metadata (\"timestamp\", \"hdkeypath\", \"hdseedid\") and relation to the wallet (\"ismine\", \"iswatchonly\").\n"
            "  \"iscompressed\" : true|false,  (boolean) If the address is compressed\n"
            "  \"label\" :  \"label\"         (string) The label associated with the address, \"\" is the default label\n"
            "  \"timestamp\" : timestamp,      (number, optional) The creation time of the key if available in seconds since epoch (Jan 1 1970 GMT)\n"
            "  \"hdkeypath\" : \"keypath\"       (string, optional) The HD keypath if the key is HD and available\n"
            "  \"hdseedid\" : \"<hash160>\"      (string, optional) The Hash160 of the HD seed\n"
            "  \"hdmasterkeyid\" : \"<hash160>\" (string, optional) alias for hdseedid maintained for backwards compatibility. Will be removed in V0.18.\n"
            "  \"labels\"                      (object) Array of labels associated with the address.\n"
            "    [\n"
            "      { (json object of label data)\n"
            "        \"name\": \"labelname\" (string) The label\n"
            "        \"purpose\": \"string\" (string) Purpose of address (\"send\" for sending address, \"receive\" for receiving address)\n"
            "      },...\n"
            "    ]\n"