  We find in one-loop calculations and spectator models that twist-3 GPDs
exhibit discontinuities. In the forward limit these discontinuities grow into
Dirac delta functions which are essential to satisfy the sum rules involving
twist-3 PDFs. We calculate twist-3 quasi-PDFs as a function of longitudinal
momentum and identify the Dirac delta function terms with momentum components
in the nucleon state that do not scale as the nucleon is boosted to the
infinite momentum frame.
