A new feature in the spectrum of ultra high energy cosmic rays (UHECR) has been announced in the paper by Berezinsky, Gazizov and Kachelrieβ. The ratio of the solution of the exact transport equation to its solution in the continuous energy loss limit shows intriguing features which, according to the Authors, are related to the very nature of the energy loss processes of UHECR: the very sharp second dip predicted at 6.3 × 1019 eV can be used as an energy calibration point and also as the UHECR mass indicator for big future cosmic ray experiments. In the present paper we would like to advocate that this statement is an overinterpretation. The second dip is a result of an inappropriate approximation used, and thus it cannot help to understand the nature of UHECR in any way.
 V. Berezinsky, A. Gazizov and M. Kachelrieβ: “Second dip as a signature of ultrahigh energy proton interactions with cosmic microwave background radiation”, Phys. Rev. Lett., Vol. 97, (2006), art. 231101.
 T. Wibig and A.W. Wolfendale: “Ultra high energy cosmic rays”, subm. J. Phys. G.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.