Alien debris in Safari. What is it?
I have a 27" iMac 3,4 GHz Intel Core i7 with 16 GB RAM running OS X 10,8.1 and a AMD Radeon HD 6970M 2048 MB Graphics Card. I have two 23" Cinema Display Screens attached to the two Thunderbolt ports.
Recently I have started to discover alien debris on my screen in Safari 6.0. It shows up randomly on certain sites, like Macrumors in the image enclosed. When I reload they appear in other positions. When I return to the site 30 minutes later, they don't appear at all. Strange.
What is it? And what could be causing it? It appears only in Safari and only occasionally.
iMac, OS X Mountain Lion, 27in 3,4 GHz Intel Core i7 16GB RAM