  We show that in van der Waals stacks of twisted hexagonal layers the
proximity induced Rashba spin-orbit coupling can be affected by quantum
interference. We calculate the quantum phase responsible for this effect in
graphene--transition metal dichalcogenide bilayers as a function of interlayer
twist angle. We show how this quantum phase affects the spin-polarization of
the graphene bands and discuss its potential effect on spin-to-charge
conversion measurements. In twisted trilayers symmetries can be broken as well
as restored for certain twist angles. This can be used to deduce the effects of
induced spin-orbit coupling on spin-lifetime anisotropy and magnetoconductance
measurements.
