  It is shown that that violation of causality in two-dimensional light-front
field theories quantized in a finite ``volume'' $L$ with periodic or
antiperiodic boundary conditions is marginal and vanishes smoothly in the
continuum limit. For this purpose, we derive an exact integral representation
for the complete infinite series expansion of the two-point functions of a free
massive scalar and fermi field for an arbitrary finite value of $L$ and show
that in the $L \to \infty$ limit we retrieve the correct continuum results.
