Swizzling behaviour into TISmartPunctuationController

SwizzlingTextView.m

@implementation SwizzlingTextView /* Subclass of UITextView */
{
    BOOL _swizzled;
}

/* working solution */
- (void)setInputDelegate:(id<UITextInputDelegate>)inputDelegate
{
    [super setInputDelegate: inputDelegate];

    if (_swizzled) return;
    _swizzled = YES;

    id smartPunctuationController = [(id)inputDelegate valueForKey: @"smartPunctuationController"];
    SEL selector = NSSelectorFromString(@"smartPunctuationOutputForInput:isLockedInput:documentState:");

    Class class = [smartPunctuationController class];
    Class subclass = objc_allocateClassPair(class, @"MySmartPunctuationController".UTF8String, 0);

    Method method = class_getInstanceMethod(class, selector);
    IMP superImp = method_getImplementation(method);

    id (^block)(id, NSString*, BOOL, id) = ^id (id self, NSString *inputString, BOOL isLocked, id documentState) {
        id result = ((id (*)(id, SEL, NSString*, BOOL, id))superImp)(self, selector, inputString, isLocked, documentState);

        /* magic */

        return result;
    };

    class_addMethod(subclass, selector, imp_implementationWithBlock(block), method_getTypeEncoding(method));

    objc_registerClassPair(subclass);
    object_setClass(smartPunctuationController, subclass);
}

@end

SwizzlingTextView2.m

@implementation SwizzlingTextView2 /* Subclass of UITextView */
{
    BOOL _swizzled;
}

/* PARTIALLY NOT working solution */
- (void)setInputDelegate:(id<UITextInputDelegate>)inputDelegate
{
    [super setInputDelegate: inputDelegate];

    if (_swizzled) return;
    _swizzled = YES;

    id smartPunctuationController = [(id)inputDelegate valueForKey: @"smartPunctuationController"];	
    [smartsuperPunctuationController swizzleMethod:self.class.smartPunctuationOutputSelector withReplacement:MZMethodReplacementProviderBlock {
        return MZMethodReplacement(id, id, NSString *inputString, BOOL isLockedInput, id documentState) {
            id result = MZOriginalImplementation(id, inputString, isLockedInput, documentState);

            /* magic */

            return result;
        };
    }];
}

@end

Please note both examples are simplified. The first solution is just fine. The second solution is much more concise, thanks to MZMethodSwizzler.h.

HOWEVER, the second solution suffers from the problem that it's not working in debug builds on device. It's fine in both debug and release in simulator, also fine in release on device. Only debug -O0 seems to fail. The super implementation's behaviour is different. One way to observe this particular example: The text replacement -- for – no longer works in this situation, while it's fine in all other cases. Replacement for " always becomes “ but never ”, e.g. on word ends.

Any advice?