Actually I get the same problem when browsing from my android phone - all browsers on it (default/ dolphin / opera).

What about software that blocks specific IP addresses using blacklists, such as Peer Guardian? The CA's often end up on those blacklists, which can cause some weirdness occasionally.

The question is, do you get the same problem when browsing from your phone using a different network (i.e. 3g/4g/anything that's not your wifi).

If the issue only happens on your home network, that could be a sign of a man-in-the-middle attack or something.

never use wifi - i get unlimited broadband. weirdly, its only when I click "my account" on gog and a few specific pages on other sites (some far more secure than this).
I actually checked details not long ago and the message it gave me seemed to be more an outdated security certificate than anything actually dodgy - but then gog isnt particularly well built for mobile borwsers anyway.
either way it doesn't worry me too much for my personal data etc as I dont have a huge amount of games on here (backed up at home where needed) and I currently dont have access to any kind of debit or credit for people to info thieve or anything.
on the other hand, i thought it would be useful for people to know that this problem / glitch is not a one off.

Edit: I should also add that when I'm on desktop I don't have this problem - even though I get my broadband by tethering my phone, so it must be a browser / browser related issue somehow.