The double-click issue started with my M65 RGB three days after I bought it. This is day five, and now the left mouse button will only work correctly if I hold it down firmly and then release it. If I release the button too soon, it tries to "multi-click" and open whatever the pointer is hovering over several times.
The way the left button feels when I depress it leads me to think this is a hardware issue, and given the number of complaints I've seen about it, I'm just gonna go ahead and take my M65 back and get a refund.
If QA is going to be such an issue for this series of Corsair hardware, I'm starting to think I got lucky in holding off on purchasing that shiny K70. :(: Very disappointing guys.
FLASH EDIT: now the left button is completely jinxed, it simply tries to highlight or select anything the pointer is tracing over no matter what kind of pressure I put on it with my finger. Yeah, this mouse is a piece of junk.