The website should set cookies for both www and non-www. It doesn't do that so if I log in to www.rotax-owner.com and then someone posts a link that is just rotax-owner.com then when I click on it I won't be signed in anymore until I add www to it. This just happened to me and it was very confusing why clicking on links to other posts on the forum would make it look like I was logged out until I got some tech help to find out why this happened.
I am logged in when I go to this link:
But I am logged out when I go to this link: