I just bought an Eotech 552 a65 that just came back from the sandbox. When you turn it on, the reticle is fine but after a few minutes it gets so fuzzy that it looks like a solid red blob. Then it will go back to normal. This cycle keeps happening every minute or two. The batteries were just changed. Has anyone else had this problem? It is out of warranty (manufactured in Jan 05). Have any of you sent one in for repair, if so, was it expensive?