it.Fail(...)..Contain(...) does not return actual value

[fogfish]

t.Run("Corrupted", func(t *testing.T) {
		it.Then(t).Should(
			it.Fail(
				func() error {
					return json.Unmarshal([]byte(geometryCorrupted), geo)
				},
			).Contain("type Unknown is not supported as GeoJSON Point"),
		)
	})

fails with

--- FAIL: TestGeometryPoint (0.00s)
    --- FAIL: TestGeometryPoint/Corrupted (0.00s)
        geometry_test.go:185: should github.com/fogfish/geojson_test.TestGeometryPoint.func3.1 return error contain type Unknown is not supported as GeoJSON Point

it is expected that actual error value is returned