Just a theory but as I know the Scirra website, once you log in to another device, you get logged out from another device.
If my theory is correct, we might be getting logged out frequently because our accounts are being infiltrated.
Or Scirra is having website issues with cookies.
It's due to some caching errors according to Tom . I don't think that all of our accounts are being infiltrated that often. Nevertheless, it's an annoying bug. When I want to read a new blog post, I know that I'll have to log in again.