Greeting interrupts Fargoth's sneak-walk
When Fargoth is sneaking to his stash during Hrisskar's quest, get close enough to him to trigger the NPC greeting. In Morrowind you'll hear the voice lines being played, but he continues in his path. In OpenMW, the greeting interrupts him, he'll stand up and idle for a while before resuming his sneaking.
So far I haven't found and other NPCs where this behaviour applies.