This has no impact on the forum’s performance, I’m just ranting a bit because it causes unexpected fees. But mostly writing down this for reference in case it happens again. 
My CDN (which serves the forum’s data from many countries to reduce latency for you guys as you live all around the globe) billed me more than 10$ for the last few days, whereas the regular cost is more like 1 to 3 dollars a month.
Discourse showed a large increase in anonymous visitors:
Bunny (the cute CDN company’s name) indeed showed a large increase in requests:
And specifically from Singapore:
A look at the monitoring statistics showed many, many requests from a single Singaporean IP:
I blacklisted this IP from Discourse Bunny 
, and I hope it will be enough to end this 
issue.
I’ll see in the next few days how it goes.