When the degree of correlation exceeds a critical value, depending on the data, it may cause the well-known effect that the resulting mean lies outside the **data** interval and its uncertainty decreases, see for example [4]. In the field of nuclear **data** this phenomenon is also known as Peelle's Pertinent Puzzle (PPP) [5]. This effect is mainly related to an incorrectly constructed covariance matrix from measurement observables, which may suggest that the used statistical model is not adequate to describe the **data** [6][7][8][9]. As a practical matter, in nuclear **data** evaluation physically unreasonable evaluated results may be generated by the least-squares method in certain extreme cases (strong correlations and discrepant input data) if no compensation for PPP is applied.