It's an interesting article Richard, but I don't see how their 2nd attempt solves the probvlem.  All it does is block the thread doing the Signal(), not other threads, from stealing the wakeup.

I think I know how to fix this correctly, using a separate internal "locking" condition variable.  I will make some offline experiments with that, to see if it makes sense, given the added complexity.  In the mean time, I will document this issue and add the link to the article you mentioned.