Ok, I already got a response:

The printed time is the end of the bar, not its begin. So the Open is naturally different. The Close is the same, but only almost - it can differ by 1 tick. The 1-tick difference has a technical reason due to the sampling. It does not affect the test results, but I admit that it might look ugly - therefore I've suggested to modify the sampling so that the closing tick is always the same.