  Recent high transverse field muon spin relaxation (TF-uSR) experiments
performed on Bi2212 single crystals show that the phase parameter extracted
from individual histogram, an indication of the angle between the muon's
initial polarization direction and the detector direction, is temperature
dependent. This phase shift effect, probably due to the electronic or initial
polarization instability at a time interval comparable with the muon spin
precession period, will affect the second moment and skewness of the field
profiles. The proper data analysis procedure is discussed to correct this phase
shift effect, which is important on the quantitative interpretation of the
first order transition or melting transition in the Bi2212 mixed state.
