Here it is: https://gitlab.idiap.ch/bob/bob.bio.video/blob/0ba8960898586974ad5da0b1d64d09406a672b12/bob/bio/video/algorithm/Wrapper.py#L312 Instead, it should be: probe = [frame[1] for probe in probes for frame in probe].

It also needs a test case to make sure this part of the code is tested too.