Does calling a virtual protected method from a base class violate the LSP?

Question

Let's say we have this base class:

class MyBase
{
    public string Name { get; set; }

    public string GetDescription()
    {
        var descriptionList = new List<string>() { this.Name };
        descriptionList.AddRange(this.ExtraDescriptions.ToList());
        return string.Join(", ", descriptionList();
    }

    protected virtual IEnumerable<string> ExtraDescriptions()
    {
        return new List<string>();
    }
}

Then add a derived class:

class MyDerived : MyBase
{
    protected override IEnumerable<string> ExtraDescriptions()
    {
        return new List<string>() { "a", "b" };
    }
}

It seems to me that this violates the LSP (because we're changing the behavior of the GetDescription method), and yet it's also a fundamental feature of object-oriented programming. The base class obviously declares its intention to allow the ExtraDescriptions method to be overridden, but this isn't necessarily visible to a consumer of the class.

Ever since I learned about the LSP, this problem has really been gnawing at me. So:

1. Does this violate LSP?
2. What's the correct alternative to this?