Two block explorers confirm that block 143692 was minted after block 143693. See http://ppc.blockr.io/block/info/143692 and http://ppc.blockr.io/block/info/143693. How is this possible?
Maybe the time stamps are made by the block finder and the clock of the finder of the latter block is faster?
I’m pretty sure that the time stamp is taken from the minter/miner internal clock. It should not be trusted too much.
Protocol allows clock drift, it applies also for BTC.