Testify mock ExpectedCall does not match expected call in gin handler, panics

Question

I'm using gin-gonic for a server, and testify for testing and mocks, along with "testing" and "net/http/httptest"

The part of the interface that mocks the method:

func (m *MockInterface) Method(ctx context.Context, id string, deleted bool) ([]models.Entity, error) {
    args := m.Called(ctx, id, deleted)

    var entities []models.Entity
    if args.Get(0) != nil {
        entities = args.Get(0).([]models.Entity)
    }

    var err error
    if args.Get(1) != nil {
        err = args.Error(1)
    }

    return entities, err
}

Setting it up in a test - the server is setup outside of this t.Run, there are tests before this that run fine.

    t.Run("TestName", func(t *testing.T) {
        mockInterface := new(mocks.MockInterface)

        mockInterface.On("Method", mock.AnythingOfType("*context.timerCtx"), id.String(), true).Return(mockResp, nil)

        // a response writer to capture the response
        rr := httptest.NewRecorder()

        url := "SomeURLString"
        // make the request to the Method handler
        request, err := http.NewRequest(http.MethodGet, url, nil)
        assert.NoError(t, err)

        router.ServeHTTP(rr, request)

        assert.NoError(t, err)
        assert.Equal(t, http.StatusOK, rr.Code)

        mockInterface.AssertExpectations(t)
    })

This is where it panics:

router.ServeHTTP(rr, request)

mock: Unexpected Method Call
-----------------------------

Method(*context.timerCtx,string,bool)
        0: &context.timerCtx{cancelCtx:context.cancelCtx{Context:(*context.emptyCtx)...etc}}
        1: "MatchingID"
        2: true

The closest call I have is: 

Method(mock.AnythingOfTypeArgument,string,bool)
        0: "*context.timerCtx"
        1: "MatchingID"
        2: false

When I go into debug mode, mockInterface.Mock.ExpectedCalls[0].Arguments[2] is true, just as I set it. And then it panics and says it's not... while it is still true!

I've gone far enough into the stack to verify that the handler called method with the boolean as true, so it ought to pass. Instead it panics, and I'm not sure where to go from here to figure out why.

Does anyone know what is going on here? Is there some kind of odd interaction between gin and testify that I'm missing? Thank you.