There's another large gap in posts from April 2015 to April 2016. I don't see any difference in the quality of English from before and after the older gap, but the gap from 2016 to 2017 does result in a significant change.
Good observation, the first gap seems to be a normal one, also the content is very similar like his utilisation of BTCPOP:
Before the first gap:
https://bitcointalk.org/index.php?topic=112447.msg11143502#msg11143502After the first gap:
https://bitcointalk.org/index.php?topic=1435851.msg14607449#msg14607449And the second gap is where the ownership changed, when he stopped managing the Zonecoin ANN and abandoned the project.
I have sent the user in question a message to respond here. Being as he is in the bustadice campaign managed by me, i'm curious to see what comes of this.
I've also sent a PM to Hhampuz.
Definitely, he changed the password before he made his first post after the gap:
November 08, 2017, 12:34:28 PM