The ones with the very small nonces are likely to be proof-of-stake blocks. Don't forget that these are also in the mix and will account for the short block time you are referring to.
Oh! That explains a lot of my confusion. The proof-of-stake implementation details are especially vague. How are those mined? (Who does the (obviously simple) computation for it and gets rewarded?) Why is P-O-S a 10 second block instead of for example folding it as an extra parallel step into hash and prime mining? The P-O-S blocks, because of their 10-15 second duration, really dominate the Nexus blockchain storage size and bandwidth.
POS blocks don't have a 10-15 second duration. They happen every 60 seconds: http://www.nexusearth.com/specs.html
Assuming Nexus POS works the same way as
proposed Bitcoin POS, there would be a POS mining channel with its own mining algorithm and reward. The
Nexus blockchain lists the hash and prime channels, but not the hidden POS mining channel. And there are no public POS miners available. So who is mining the POS blocks and what is their reward?
Maybe the POS miner is built into the
wallet? That would explain why the wallet uses so much CPU constantly. Do open wallets sometimes get random POS mining rewards?