I had noticed that also. Though the links are there, they are almost invisible to the eye. Nice to know it is being worked on and will hopefully be back to normal soon.
From what I am seeing, the "Already clicked" display color is nearly the same if not the same color as the background, so they are fading in. I tried changing my theme, and have found it to be an issue in at least 3 different themes. The website guys should get that updated before too long, as it IS a glaring error. If you clear your cache, you will suddenly find them quite visible until you click on them again.