Avalonia Realtime sample crashes with Avalonia version 11.3.7 or later

[frubenas]

The Avalonia General/RealTime sample crashes with the following exception:

Exception has occurred: CLR/System.NotSupportedException
An exception of type 'System.NotSupportedException' occurred in System.ComponentModel.TypeConverter.dll but was not handled in user code: 'StringToDoubleArrayTypeConverter cannot convert from Avalonia.Markup.Xaml.MarkupExtensions.CompiledBindingExtension.'

The issue seems to be related to the binding for CustomSeparators; without the CustomSeparators attribute in the XAML file, the exception is not thrown.

To Reproduce
Steps to reproduce the behavior:

1. Change AvaloniaVersion value to 11.3.7 (currently the latest version is 11.3.11)
2. Run the AvaloniaSample.Desktop project
3. Select General/RealTime
4. See error

Desktop (please complete the following information):

• OS: Linux (but I think it should be visible on any platform)
• Version 2.0.0-rc6.1