I have been noticing that double spaces are often occuring when I type on my modded Cherry G80-3000. The problem is, I don't know if it's the keyboard or if it's me. I know that it never occurs with the Logitech rubber dome at work, but that might just be because the keys on that require more of a mash than the Cherry MX browns.
To put the resistance theory to the test, I swapped in a tactile grey MX top and spring, but still have the problem.
I remember it having this problem to some extent when it was originally an MX Blue + Green keyboard, so it's not a result of the switch top swaps. Recently though, I have been noticing it more often but don't know if that's because I'm being more observant or because it is happening more often. None of the other keys do it - just the space bar.
If I try to reproduce the problem, such as by typing a a a a a a a a a a a a, I can do that many, many times and never see the repetition.