Html.ActionLink() Gives An Empty Link When Use It Inside Html.RenderAction()?

I have a Microsoft MVC project with an action "Foo" whose view ("Foo.aspx") contains the lines:

<%= Html.ActionLink("mylinktext1", "bar") %>
<%= Html.ActionLink<MyController>(x => x.Bar(), "mylinktext2") %>

When I hit this from a web browser or load it from an AJAX call, it properly returns:

<a href="/bar">mylinktext1</a>
<a href="/Bar">mylinktext2</a>

But when I call the action from another view like this:

<% Html.RenderAction<MyController>(x => x.Foo()); %>

Then the links are rendered without targets.

<a href="">mylinktext1</a>
<a href="">mylinktext2</a>

Why would this be happening, and how do I work around it?