A circular reference！

I add the method in StrechyHeaderExampleViewController.m
- (void)dealloc
{
NSLog(@"Release Success");
}

It's never performed.

Then I change strong to weak in MultiplexerProxyBehaviour.h

@property(nonatomic, weak) IBOutletCollection(id) NSArray *targets;

And then dealloc method is performed.
So,what is the reason you used strong ?
Thank you

Start with MultiplexerProxyBehaviour.h and StrechyHeaderExampleViewController.m, then trace how the IBOutletCollection targets are retained and released. Compare the deallocation behavior with strong and weak ownership, and confirm the intended lifecycle for the targets. Done means the ownership choice and resulting deallocation behavior are explained or resolved consistently.

Written by the indexing model from the issue text.