bitcoind validateaddress extended info.. somtimes there, somtimes not, why? I have noticed sometimes ./bitcoind validateaddress [addr] produces an extended output, like this:

./bitcoind validateaddress mjYvqa4tC4oEC2ATQrcJh9Ux3CLcszW5J9
{
    "isvalid" : true,
    "address" : "mjYvqa4tC4oEC2ATQrcJh9Ux3CLcszW5J9",
    "ismine" : true,
    "isscript" : false,
    "pubkey" : "03ab4a26a0d577bb4dd5c46b49c1dd19a30a582a5b317f952e490eaac86564fdc0",
    "iscompressed" : true,
    "account" : ""
}


And other times, when I validate and address it looks like this: (why?)

./bitcoind validateaddress n3t74UDtWZtBSVbF5DLxm4ViFiU7rRY5gm
{
    "isvalid" : true,
    "address" : "n3t74UDtWZtBSVbF5DLxm4ViFiU7rRY5gm",
    "ismine" : false
}
Note the difference: one has "ismine" true and in the other it's false.

I haven't specifically checked, but I presume that "ismine" indicates whether or not the address is one belonging to you (and whose key is in your wallet).  If it is your address, then bitcoind is able to report the associated public key, and various other details about how the key is stored and notes associated with it.

If the address is not yours, then since the address is only a hash of a public key, there is no way for bitcoind to know what the public key itself is, nor any other information about how the owner is storing the key, etc; that information is known only to the key's owner.  So you don't see these fields in the output.