Yes, the AI sometimes uses the force beaming. I had once observed it in Spain where an army of Lusotans was able to get form southern Spain to the very north of it in one turn ignoring all ZOCs from my towns, armies and fortresses. Another time I saw a Ptolemaian army that made it from Alexandria to Sidon in the speed record of one turn.

There are other examples where I often thought "eh? where did these come from?!?", when an enemy full stack appeared out of the nowhere excaactly where the AI desperatly needed troops.