logged in to the site a few minutes ago, i have all yellow icons for new topics/reply's but after reading two topics all the "new topic" icons have gone grey without me reading the new topics or using the forum tools to set them read.
I've noticed this too. It's annoying... I always have to open every link I'm interested in in new tabs to not lose track of what I've already read and whatnot.
I've noticed this as well, it's not just you. As to why this is happening when I saw them Orange a minute ago, who knows right now. I seem to notice it happens when I click the x10Hosting banner at the top of the forum. Seems half of the time I click that it marks all posts as read.
I'm actually getting the exact opposite results; the yellow icons never go away until I log out, even if I finished reading all the threads in that section of the forums.
Also, I noticed that the yellow icon appears after I make a post myself in a previously read board.
I believe this is a setting somewhere in the options... how long to mark items as 'new' for. I have no idea where I saw this setting last so I'll have to dig around for it. Remind me in a few days if it's still not fixed ;P