But has Scirra/Construct filed or notified Apple of this problem as an engine developer?
So far I don't believe I've been able to reproduce the problem myself. We cannot file a bug report if we can't reproduce the problem - if it looks like everything works, how can we tell Apple it's broken? Getting us to reproduce the problem is just an unnecessary extra step anyway, as all we'd do is forward the issue on to Apple. So it will be quicker to cut us out and report the problem directly.
Does Scirra have a contact at Apple or relationship they can follow up on?
Absolutely not. Apple are notoriously secretive to the point of absurdity, e.g. they mark bugs as fixed but can't tell us when the fix will ship, only saying "Apple does not comment on future releases" as a standard response. If Apple made anyone available to us, we'd definitely talk to them about such issues, but they do not make any such person available nor do they appear to have a culture that would be open to such an idea.
So in short, you're probably best off reporting iOS regressions directly to Apple. No software is perfect, all platforms have bugs and occasional regressions - this really is business as usual in the software world. And if people keep trying to pressure us to do something about it when it's impossible for us to do anything about it, it will only make it take longer to solve the problem. This has happened before in other ways and to be honest it's pretty frustrating for us; I know you all just want it to be fixed but it is genuinely out of our hands and we have few options - Apple need to fix it and if you keep telling us to do something about it then you'll get nowhere, because so far there's nothing we can do.