I started to look at the Flex videos he made. I gave up pretty soon, but see that in spite of the unfortunately rather long-winded moaning, there's stuff that can be improved in Logic's Flex engine.
Extremely well-documented vid of more L9 bugs
With all due respect, it looks more like a number of way-too-long clips, made by one who hasn't read the manual, on a un-supported Mac, trying to show how Flex behaves if you want to use Flex for something else than what it probably was primarily intended for.

He does seem to document bugs as well, but wouldn't a short description of a bug make it more likely that someone from Apple would read and try to recreate this than spreading his feedback over all these videos? I don't know...
I'm basically all for not having to be dependent on manuals, but some of the stuff in this videos seems like perfect examples of situations where spend a little with trying to understand how new, complex feature is
intended to work would make sense.
Nevertheless - I sometimes hear unexpected pops and 'quantizations' when using Flex as well. I'm not totally shocked - after all, this is the first version of Flex, but it does seem like Logic needs a way to force itself to totally ignore non-relevant transient markers that aren't relevant when quantizing.