It's clearly from the very last legal meaning, which is
as explained here. Compare the synonym in the last quotation -
resolvere, that is "
to untie, unfold back something that has been
tied or
folded together, concluded by the defendant's previous statement". The defendant
ties the case
up, the plaintiff
unties it
again.
I'm not sure what type of material was used in the late Empire to present legal statements:
replicāre implies wooden tablets (if not sheets of parchment) while
resolvere must refer to a scroll. But since the meaning "to go over again in the mind" is earlier than this, the legal use is easiest to derive from this latter one without the need for a metaphor involving any written medium.