I want to know what changes typically trigger the invocation of NSKeyValueWillChangeWithPerThreadPendingNotifications in CAAnimation_setter, and whether changes to the object make object_getClass ineffective.

Are you using the MBProgressHUD? I may have found a potential cause of the crash, if MBProgressHUD is initialized with blur style and UIVisualEffectView is added, if I call some UI operation at the same time, the application will call -[NSObject(NSKeyValueObserverNotification) willChangeValueForKey after UIVisualEffectView receives dealloc call :], which may have caused the crash shown on the stack. I'm not 100% sure since crashes happen rarely, but I've observed this in instruments.

I solved my problem, actually there is no label type marked in SDWebImage's PrivacyInfo.xcprivacy , so no information will be included in the final PDF.

Finally, I end up with encoding depth buffer as additional video output, but the 8 bit precision is insufficient.