badges only show up when the thread tags show it as relevant, otherwise they are not visible unless you look at a users profile. the only badge which shows 100% of the time every time are special cases like mod/staff/admin stars.
for instance if a post is about cpus and the tag "cpu" is placed (normally this happens automatically) then it will show the cpu badge if you have one. if the post is about nvidia graphics cards you might see badges for graphics cards and nvidia show up for badge icons.
if it was there on a post then not there later perhaps the thread's tags changed. you still have the cpus green badge.