Unless it’s Russia, Iran, or NK, it’s probably not a weapon. Nothing to be gained diplomatically.

There was some stories suggested that this was cause by interference of two survelience bugs.

I agree with you, but there was some speculation that it could be Russia trying to ruin diplomatic ties between the US and Cuba. And Russia does have quite the history of abusing diplomats (though typically only within Russia.)

This article just recently came out on the topic: https://www.politico.com/magazine/story/2018/05/19/michael-m...

So why would they attack some poor chap in China?

I could see Russia trying to stir the pot because formenting chaos with plausible deniability seems to be part of Putin’s strategy toward the west, although I would have imagined that the UK would be a more recent target. NK is trying to dethaw relations so that doesn’t make much sense. That leaves you with Iran. Unless of course it’s not a weapon at all. It could even be interference with US counter survalience technology.