A simple way to make sure there is only one scrollview which is able to scroll to top at a time

UIScrollView+ScrollsToTop.h

#import <UIKit/UIKit.h>

@interface UIScrollView (ScrollsToTop)

+ (void)forceNewViewsDefaultValueForScrollsToTop;
+ (void)makeOnlyThisScrollViewScrollToTopOnStatusBarTap:(UIScrollView *)scrollView;
- (void)makeOnlyThisScrollViewScrollToTopOnStatusBarTap;

@end

UIScrollView+ScrollsToTop.m

#import "UIScrollView+ScrollsToTop.h"
#import <objc/runtime.h>

__weak static UIScrollView *s_currentScrollTopTopScrollView;
static void * const AGDidAddObserverKey;

@interface UIScrollView ()

@property (nonatomic, assign) BOOL didAddScrollToTopObserver;

@end

@implementation UIScrollView (ScrollsToTop)

static void SwizzleMethods(Class c, SEL orig, SEL new)
{
    struct objc_method *origMethod = class_getInstanceMethod(c, orig);
    struct objc_method *newMethod = class_getInstanceMethod(c, new);
    if(class_addMethod(c, orig, method_getImplementation(newMethod), method_getTypeEncoding(newMethod)))
        class_replaceMethod(c, new, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
    else
        method_exchangeImplementations(origMethod, newMethod);
}

+ (void)load
{
    [self forceNewViewsDefaultValueForScrollsToTop];
}

+ (void)forceNewViewsDefaultValueForScrollsToTop
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        SwizzleMethods([UIScrollView class], @selector(didMoveToWindow), @selector(AGS_didMoveToWindowNew));
    });
}

+ (void)makeOnlyThisScrollViewScrollToTopOnStatusBarTap:(UIScrollView *)scrollView
{
    if(s_currentScrollTopTopScrollView != nil)
    {
        s_currentScrollTopTopScrollView.scrollsToTop = NO;
    }
    
    s_currentScrollTopTopScrollView = scrollView;
    
    if(s_currentScrollTopTopScrollView != nil)
    {
        s_currentScrollTopTopScrollView.scrollsToTop = YES;
    }
}

- (void)makeOnlyThisScrollViewScrollToTopOnStatusBarTap
{
    [[self class] makeOnlyThisScrollViewScrollToTopOnStatusBarTap:self];
}

- (void)AGS_didMoveToWindowNew
{
    [self AGS_didMoveToWindowNew];
    
    if (self.window != nil)
    {
        [self disableScrollsToTopIfNotTheChosenOne];
        [self addObserver:self forKeyPath:@"scrollsToTop" options:(NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld) context:NULL];
        self.didAddScrollToTopObserver = YES;
    }
    else
    {
        [self disableScrollsToTopIfNotTheChosenOne];
        if(self.didAddScrollToTopObserver)
        {
            [self removeObserver:self forKeyPath:@"scrollsToTop"];
            self.didAddScrollToTopObserver = NO;
        }
    }
}

- (void)setDidAddScrollToTopObserver:(BOOL)value
{
    objc_setAssociatedObject(self, AGDidAddObserverKey, @(value), OBJC_ASSOCIATION_COPY_NONATOMIC);
}

- (BOOL)didAddScrollToTopObserver
{
    NSNumber *value = objc_getAssociatedObject(self, AGDidAddObserverKey);
    return [value boolValue];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    [self disableScrollsToTopIfNotTheChosenOne];
}

- (void)disableScrollsToTopIfNotTheChosenOne
{
    if (self != s_currentScrollTopTopScrollView && self.scrollsToTop == YES)
    {
        self.scrollsToTop = NO;
    }
}

@end

X Example app delegate

/*
 * NOTE: In your info.plist you need to set "View controller-based status bar appearance" to "NO"
 */

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    [UIScrollView forceNewViewsDefaultValueForScrollsToTop];
    return YES;
}