The problem of reliability of the photoneutron partial reaction cross sections for $^{75}$As, $^{127}$I and $^{181}$Ta obtained in experiments used the beams of quasimonoenergetic annihilation photons was considered using the objective physical criteria. It was shown that the experimental data for (𝛾, 1𝑛) and (𝛾, 2𝑛) reactions cross sections for three mentioned nuclei obtained using the method of neutron multiplicity sorting are not reliable because contain significant systematic uncertainties. It was found that additionally to uncertainties of unreliable determination of neutron multiplicity basing on its measured energy the significant uncertainties of different nature exist. Using the comparison of experimental cross sections with those evaluated using experimental-theoretical method it was shown that additional uncertainties are due to the loss of noticeable part of neutrons from the reaction (𝛾, 1𝑛) in the cases of $^{127}$I and $^{181}$Ta and from the both (𝛾, 1𝑛) and (𝛾, 2𝑛) reactions in the case of $^{75}$As.
$^1$Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moskow 119991, Russia.\
$^2$Faculty of Physics, M.V. Lomonosov Moscow State University.
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