I have splurged and bought the very expensive Corsair K90 keyboard.
I encountered a very odd firmware bug in it. It will occasionally (once every few days) have a key get "stuck" as if being held down. However the key is NOT physically jammed.
-When this occurs the keyboard will continue to send this keypress signal continuously until ANY key is pressed. That means that if the F3 key is "firmware stuck" then I can press the spacebar and it will unstuck it (this makes it hard to detect as rapid typing can hide this effect as you unstuck a key before it is noticed).
-I have seen it happen for a variety of letter keys, space bar, enter, and F keys.
-There is absolutely no indication of there being any physical issue
all the above combined suggest to me that this is a firmware issue.
I have tried updating the firmware and driver (as per instruction from their customer support).
Now, several months after I bought the keyboard my space bar key broke. I got the keyboard replaced under warranty... The new one they sent me has the exact same issue with the "firmware stuck" keys.
I also updated it to firmware 1.19 and it has the same issue.
I was wondering if other people are experiencing the same issue and how common it is. There was no indication of such a defect in the anandtech review of the keyboard (which is really what sold me on it).