I bought this Corsair Cherry MX red keyboard back in November 2015 and it certainly has been a pleasure to type on up until recently.
Over the past few weeks, I found myself correcting an unusual number of double L's and thought it may the way I was sitting or holding my right hand. From a quick test in notepad, I started typing 'L' + Enter in a loop for curiosity. After several iterations, I got two L's on a line and began to realise that this is the keyboard.
Sure enough from a quick search, it looks like I've been hit with the Cherry MX key chattering issue.
For anyone else affected, there's a little utility called 'Keyboard Chattering Fix' (link), which blocks duplicate key presses within a specified interval.
The following is a screenshot of it in action, which shows how bad the chatting issue is with my keyboard. It's not perfect as it occasionally misses the 'L' chatter, although I may try increasing the threshold to 60ms. The 'H' and 'C' keys now intermittently chatter on my keyboard: