I can't reproduce the issue anymore. However, that's weird to see that others people are redirected to others strange websites.
Typing "m.facebook.com" is not enough, because it require forcing http → "http://m.facebook.com" (notice the "http://" as prefix). Plus, if the DNS server hypothesis (see below) is correct and we don't use the same Opera Turbo server, maybe you're not at risk. Because I'm in France, according to a network sniffing app, I use a Opera Server located in the Europe.
Try cleaning up cached files and cookies, maybe even doing a Malwarebytes scan
Clean cache is not enough : next time I went to http://m.facebook.com, I was redirected with Opera Turbo/Data saving mode. But it was enough to go to genuine Facebook without Opera Turbo/data saving mode.
Malwarebyte scan → done.
First I suspected some Kind of DNS poisoning.
Same. As far as I understand, when you use Opera Turbo/data saving mode, you use Opera DNS servers. That would mean Opera DNS servers are not trustworthy.
So I tried several Android Virus Scanners and I found Android/domob.A within Android Assistant.
What scaner did you use ?
Maybe virus attacked your device.
devices*. That's highly unlikely, because :
- 1 of the 3 smartphones tested never accessed the Play Store before downloading Opera, no third-party app from an other store ... Just default apps.
- on these 3 smartphones, http://m.facebook.com always redirected to the SAME website (tabor.ru)
- the redirection happens ONLY when those two conditions were met :
- Browser is Opera Android
- Opera Turbo/data saving mode is enabled