Invalid instantiation exception when pass dynamic object to custom interpolated string handler in .NET 6

Question

I found an issue upgrading to the .NET 6 LogErrorInterpolatedStringHandler in my logger method.

Here is the classic method:

public static void Log(string message, params object[] pars)
{
    // Log message
}

and here is the upgraded one:

public static void Log(ref LogErrorInterpolatedStringHandler message, params object[] pars)
{
    // Log message
}

I upgraded the method in order to get the performance improvements of C# 10 and .NET 6 described here.

The new version of the method works well except when passing dynamic object in the interpolated string.

Here is an example:

// Works well   
Logger.Log($"Log: {stringOrEverythingElseObject}");

// Exception
Logger.Log($"Log: {dynamicObject}");

The exception thrown is

The generic type '<>A{00000004}`3' was used with an invalid instantiation in assembly 'MyAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.

I found a pull request similar to my problem but could not understand how to fix in my code.

Do you have any idea? Thanks!