Why isn't my test method executing?

I have a fairly complex integration test that requires a lot of data in each distinct test case.

My test case class is as follows:

public class TestCases
{
  public static IEnumerable MatchingCases
  {
    get
    {
      yield return
        new SearchSetup
        {
         MinimumMatches = 1,
         BulletinSetups = new List<BulletinSetup>
                      {
                        new BulletinSetup
                          {
                            ParameterSetups = new List<ParameterSetup>
                                     {
                                       new ParameterSetup
                                         {
                                          FieldName = "Number",
                                          ParameterName = "@Number",
                                          Value = "TBS1001" + DateTime.Now.ToLocalTime()
                                         }
                                     }
                          }
                      },
         FilterValues = new Dictionary<string, object> { { "Number", "TBS1001" } }
        };
    }
  }
}

The header of my test method is:

[Test, TestCaseSource(typeof(TestCases), "MatchingCases")]
public void Search_VariableFilter_NoAccountTeam_ResultIncludesExpected(SearchSetup searchSetup)

When I run the test, it returns inconclusive. When I step thru the code, I find that the MatchingCases property getter is being accessed, and the yield return statement executes w/o issue, but the test method itself is not called - or rather, not predictably.

See, I wrote this question up once already, then I tried moving the test class out of the testfixture scope. When I did that, the code executed once, and so I dumped my question. Then it stopped executing anymore...

Why isn't my test method being called?

Edit: Anticipating the question - these are the supporting classes being used:

public class ParameterSetup
{
    public string ParameterName { get; set; }
    public string FieldName { get; set; }
    public object Value { get; set; }
}

public class BulletinSetup
{
    public List<ParameterSetup> ParameterSetups { get; set; }
}

public class SearchSetup
{
    public List<BulletinSetup> BulletinSetups { get; set; }
    public int MinimumMatches { get; set; }
    public Dictionary<string, object> FilterValues { get; set; }
}

Update - next day

After closing and reloading Visual Studio, and rerunning the test with no changes of any kind, the test code executes, repeatedly. I'm beginning to suspect this was a transitory glitch.

Since reloading VS the test method executes fine. I'm chalking it up as a glitch to close this question out.