The unexplained disagreement in the dependence of spectroscopic factors ( C 2 S exp ) on the binding energy obtained by nucleon knockout using different targets is still a puzzle that needs to be addressed. To find an explanation of this riddle through exclusive measurements using different targets. The exclusive measurements were performed by using a Ne 17 beam with an energy of 500 MeV/u incident on C and CH 2 targets. Through the standard theoretical approach, C 2 S exp were derived from the analysis of the experimental data on proton ejection from the proton halo in Ne 17 as well as from its core O 15 . For the C target, proton ejection from the proton halo gave C 2 S exp about 37% smaller than for the H target. But when protons are ejected from the core of Ne 17 , C 2 S exp are identical within statistical uncertainties. An explanation for the difference in C 2 S exp could be the removal of both halo protons, a more important reaction pathway for the C target. The C 2 S exp values obtained by analyzing the proton ejection from the core indicate that it is not affected by the interaction with the halo protons. Published by the American Physical Society 2024