why hook systemFontOfSize cause app crash?

[Dast1Woop]

when I put the following code in category or homeViewController, the app will crash: [UIFont st_hookClassMethod:@selector(systemFontOfSize:) option:(STOptionInstead) usingIdentifier:(@"myHook_fontWithSize") withBlock:^UIFont * (id<StingerParams> params, CGFloat oldPara){ UIFont *oldRet; [params invokeAndGetOriginalRetValue:&oldRet]; CGFloat newSize = oldRet.pointSize * 2; return [UIFont fontWithName:oldRet.familyName size:newSize]; }];

the crash info is: 2023-06-28 18:00:33.468715+0800 ChangeFontSizeTest[1784:376274] [Assert] UINavigationBar decoded as unlocked for UINavigationController, or navigationBar delegate set up incorrectly. Inconsistent configuration may cause problems. navigationController=<UINavigationController: 0x15c01c200>, navigationBar=<UINavigationBar: 0x15bd09d50; frame = (0 59; 0 50); opaque = NO; autoresize = W; layer = <CALayer: 0x2833c74c0>> delegate=0x15c01c200

pls help!