> Vietnam, Brazil and Angola

Curiously, these are some of the top countries I see when analyzing traffic from malicious scraping bots that disguise themselves as old Chrome versions on my websites.

So it's possible that one of those botnet-ish residential proxy services is being used here. The ones that use things like compromised browser extensions to turn unknowing users into exit nodes.

Edit: Yep, it's residential proxies, someone on the linked page mentioned a website where you can look up the IPs and all of them come up as proxies.