[emedchill]

Without you proving an example, my best guess is that the site is using weak ciphers or old SSL/TLS versions. Technically, it has some security but not good enough by today's standards.

If you run into that issue again, try running it though https://www.ssllabs.com/ssltest/

[emedchill]

It could also be that your phone has some sort of MITM or packet sniffing program that is doing an insecure redirect, capturing your intended destination then sending you to it.

[gtirloni]

Could a captive portal be doing that? How would it capture my request? Maybe DNS intercept that redirects me to some of its servers before doing a redirect?

I don't think I have an app sniffing my phone. It's not rooted and it happens semi-randomly.

[gtirloni]

I mentioned it happened on HN (news.ycombinator.com) just before I posted this submission.