Crash on iPhone 6 on iOS 12 with Realtime Database

Start with the ReadSomeValueChange method and its ValueChanged subscription, then reproduce the report in the samples project on an iPhone 6 running iOS 12. Compare the behavior with later iPhones and verify that registering the Realtime Database listener no longer crashes and that the callback can run.

[REQUIRED] Please fill in the following fields:

• Unity editor version: 2021.3.32f1
• Firebase Unity SDK version: 11.6.0
• Source you installed the SDK: Unity package manager via tgz
• Problematic Firebase Component: Realtime database
• Other Firebase Components in use: None
• Additional SDKs you are using: None
• Platform you are using the Unity editor on: MacOS 14.0 with xCode version 15.0.1
• Platform you are targeting: iPhone 6 iOS 12.5.7
• Scripting Runtime: IL2CPP

[REQUIRED] Please describe the issue here:

When trying to register for a value changed in the realtime database, the app crashes on the iPhone 6. This only occurs on the iPhone 6 and not on later iPhones. When the app crashes, xcode outputs a cryptic message:

0x100aa4000: .long 0xfeedfacf ; unknown opcode

Steps to reproduce:

• Install firebase through the package manager
• Add GoogleService-Info to the project
• Add the script below (see following section)
• Build the project through xCode
• Notice the crash on iPhone 6.
• Notice that the crash does not occur on more 'modern' iPhones, which my collegues have

I was also able to reproduce this issue in the samples project.

I also tried downgrading the firebase SDK to 10.6.0 and the issue also occured here.

Relevant Code:

public void ReadSomeValueChange()
    {
        string dataBaseUrl = "https://<yourfirebaseurl>.firebasedatabase.app/";
        Debug.Log("Before getting instance");
        var dataBase = FirebaseDatabase.GetInstance(dataBaseUrl);
        Debug.Log("Before getting reference");
        var somePath = dataBase.GetReference("/test");
        Debug.Log("Before registering to value changed");
        somePath.ValueChanged += HandleValueChanged; // APP CRASHES HERE
    }

    private void HandleValueChanged(object sender, ValueChangedEventArgs args)
    {
        // app does not reach this line
        Debug.Log("Value changed");
    }