Don't know if you noticed you're posting on a thread that's over 5 years old. All of the people on this thread are most likely long gone and won't be replying to your post.
This separated shoe lining happened to me on one of our Aveos. So with two of this same thing, it's certainly more than just an oddball fluke, but probably can't be called systemic without more history. But getting much more information very unlikely to happen here, because this forum is currently a very quiet place. There are very few active, regular members, and just a handful of us into DIY (along with a couple current or former pros). There have been a number of really good DIYers here in the past, and the archive has lots of helpful information. But most everyone these days just posts about problem once or twice and goes away, never to return.
You sound like someone with a lot to offer to a forum like this, and it would be nice to see you stick around. But I just wanted to give you a heads-up that you won't be seeing a big pile of replies to things that you post. And of course that's not unusual, because lots of these forums are just as sparse as this one, and some are even much worse. It's just the way it is.