RichText failure with <margin> tags

<link="MultiStripGPUEvents.vfx"><color=#7AA8EEFF>Open VFX</color></link><br><link="VFXG Multi-Strips GPU-Events"><color=#FFE373FF>Show VFX</color></link><br><br>There are several ways to spawn particles, and when dealing with <b>strips</b>, this can have some implications for how you need to set up your VFX. This example illustrates how to circumvent the usual limitation that only permits the creation of one strip per parent's particle when dealing with <a href="https://docs.unity3d.com/Packages/com.unity.visualeffectgraph@latest/index.html?subfolder=/manual/Block-TriggerEventRate.html">Trigger Events</a>. Each headphone jack is made of a particle mesh and spawns particles along its path.<br><br><b>Covered Aspects</b>:<br><margin=1em>• <a href="https://docs.unity3d.com/Packages/com.unity.visualeffectgraph@latest/index.html?subfolder=/manual/Context-OutputShaderGraphStrip.html">Strip Output Context</a><br></margin><margin=1em>• <a href="https://docs.unity3d.com/Packages/com.unity.visualeffectgraph@latest/index.html?subfolder=/manual/Operator-GetAttributeStripIndex.html">Strip Index</a></margin>

public class ReproRichText : EditorWindow
{
    [MenuItem("CLICK HERE FOR REPRO/Repro Rich Text")]
    public static void ShowExample()
    {
        ReproRichText wnd = GetWindow<ReproRichText>();
        wnd.titleContent = new GUIContent("Simple Label");
    }

    public void CreateGUI()
    {
        var myLabel = new Label();

        myLabel.text =
            "<link=\"MultiStripGPUEvents.vfx\"><color=#7AA8EEFF>Open VFX</color></link><br><link=\"VFXG Multi-Strips GPU-Events\"><color=#FFE373FF>Show VFX</color></link><br><br>There are several ways to spawn particles, and when dealing with <b>strips</b>, this can have some implications for how you need to set up your VFX. This example illustrates how to circumvent the usual limitation that only permits the creation of one strip per parent's particle when dealing with <a href=\"https://docs.unity3d.com/Packages/com.unity.visualeffectgraph@latest/index.html?subfolder=/manual/Block-TriggerEventRate.html\">Trigger Events</a>. Each headphone jack is made of a particle mesh and spawns particles along its path.<br><br><b>Covered Aspects</b>:<br><margin=1em>• <a href=\"https://docs.unity3d.com/Packages/com.unity.visualeffectgraph@latest/index.html?subfolder=/manual/Context-OutputShaderGraphStrip.html\">Strip Output Context</a><br></margin><margin=1em>• <a href=\"https://docs.unity3d.com/Packages/com.unity.visualeffectgraph@latest/index.html?subfolder=/manual/Operator-GetAttributeStripIndex.html\">Strip Index</a></margin>";
        myLabel.enableRichText = true;

        rootVisualElement.Add(myLabel);
    }
}