I was affected by this breaking my 32bit app so I remember my digging. While your plugin/app does not link against MobileDevice framework(which is updated silently[or was] whenever an iOS device was plugged into your mac), CoreAudioKit does.
otool -L /System/Library/Frameworks/CoreAudioKit.framework/Versions/A/CoreAudioKit
I don’t think there’s too much the JUCE team can do… Well… CoreAudioKit is only used for AU views, so I suppose there could be some fiddling around so it’s not linked for AAX plugins, but AU will still be broken. There’s probably more frameworks that link against MobileDevice as well, I just stopped looking after that!