Moq not matching method

I have a method

Task<Document> GetCampaignById(Tenant tenant, string language, string campaignId);

that I am trying to mock:

mockLocator.Setup(l => l.GetCampaignById(
                It.IsAny<Tenant>(),
                It.IsAny<string>(),
                It.IsAny<string>()))
            .Returns(Task.FromResult(dummy));

I did, at first have "not set up" output but I am not getting any at all now and the test just shows as failed. I have tried changing to ReturnsAsync(dummy) but that did not alter my output at all. moq is set to strict but I don't think that should matter.

As far as I can tell I am setting this up with the correct parameter types and the correct return type but the test seems to fail before it even starts. Can anyone shed any light on this?

Full Test

[TestCase(1)]
[TestCase(2)]
[TestCase(3)]
[TestCase(4)]
[TestCase(5)]
public async Task ShouldCallUpdaterForEveryTenantResolved(int tupleCount)
{
     // Arrange
    var tenantTuples = CreateTenantTuples(tupleCount);

    var mockTenantResolver = MockRepository.Create<ITenantResolver>();
    mockTenantResolver.Setup(tr => tr.GetTenantTuples(It.IsAny<string>()))
        .Returns(tenantTuples);

    var mockCampaignIngestionService = MockRepository.Create<ICampaignIngestionService>();

    var dummy = new Document();           
    var mockLocator = MockRepository.Create<IVehicleSearchStockUpdater>();
    mockLocator.Setup(l => l.GetCampaignById(
        It.IsAny<Tenant>(),
        It.IsAny<string>(),
        It.IsAny<string>()))
    .Returns(Task.FromResult(dummy));

    mockLocator.Setup(l => l.UpsertNewStockLevel(
        It.IsAny<Document>(),
        It.IsAny<OmegaConnector.Functions.PartnerCommunicator.Models.ChangeStockInfo>()))
    .Returns(Task.FromResult(dummy));

    var sut = new CampaignIngestionProcessor(
        mockTenantResolver.Object,
        mockCampaignIngestionService.Object,
        mockLocator.Object);

    var data = GetSimpleTestData();
    data.NewStock = 5;

     // Act
    await sut.SubmitChangeStock(data);

    // Assert           
    mockLocator.Verify(l => l.GetCampaignById(
        It.IsAny<Tenant>(),
        It.IsAny<string>(),
        It.IsAny<string>()), 
        Times.Exactly(tupleCount)
    );

    mockLocator.Verify(l => l.UpsertNewStockLevel(
        It.IsAny<Document>(),
        It.IsAny<OmegaConnector.Functions.PartnerCommunicator.Models.ChangeStockInfo>()),
        Times.Exactly(tupleCount)
    );
}