There's gotta be a fork.
Block 605660 as reference:
{
"hash" : "45fa763eaf7ab824740145a0e953433cb2ca4533e352a8dcf9830dd5a7d87960",
"confirmations" : 4,
"size" : 214,
"height" : 605660,
"version" : 1,
"merkleroot" : "9e9325d0be1c7b8e2f45ae5e7a2f988f1b31fd55a6a6add2981b35f57e1df2f3",
"tx" : [
"9e9325d0be1c7b8e2f45ae5e7a2f988f1b31fd55a6a6add2981b35f57e1df2f3"
],
"time" : 1378789323,
"nonce" : 3999076096,
"bits" : "1d0089b9",
"difficulty" : 1.85877982,
"previousblockhash" : "923f37f9256bcffd4adc15f2117810f9173a6fc7cae4cbcc24c149bdb4195bed",
"nextblockhash" : "1f274ae83cc03b64437593cbcfbbc0a790ccf1ec9dead14466a90325ca16db88"
}
Yeah, the issue is with one of the pools..don't know if any other is involved.
So far I'm mining solo with great results and everything seems to be in order. Be aware though..that there could be trouble..so let's check the blockchain from time to time