I think I may have found out the reason for sticky ergo-clear switches. I've read about this before and some people have mentioned that it has something to do with the lightness of the spring.
I was trying to figure out why one or two of my ergo-clear switches were sticking on the upstroke, so I decided to take apart a sticky switch and a non-sticky switch. The metal contact circled below was bent on the sticky switch and I suspected this to be the cause. I had an extra MX Red switch laying around, so I took it apart and replaced the red stem with a clear one. The stickiness disappeared.
It couldn't have been the lightness of the spring since wide-spread stickiness hasn't really been reported.

What do you guys think? I haven't tried to replicate this yet with another sticky switch, so I can't be absolutely certain that it's sure thing.