  The quantum oscillation is an important probe for the detection of a
topological insulator(TI) surface states by means of electrical transport since
the Shubnikov-de Haas oscillations allow to extract the Berry Phase which is
the key test to detect the topological surface states. Here we have extracted
the non trivial Berry Phase of 1$\%$ Sn doped strong TI $Sb_2Te_2Se$. We
observed oscillation in Hall resistance as well and showed that this does not
arise neither from the dominance of the SdH on Hall data nor this is the
precursor of quantum Hall effect, rather this happens due to the pinning of the
Fermi Level. Also The Hall oscillation has exactly 180$^\circ$ phase difference
from SdH oscillation and this phase shift is independent of the magnetic field
strength. It is argued that this unusual phenomenon stems from the predominance
of the intra Landau Level scattering over the inter Landau Level scattering and
it depends on the strength of the scattering potential. Thus our work paves the
way of understanding the physics of scattering via quantum oscillations.
