Why does my Ai Character stop animating when off-screen or occluded?

I’m having an issue where enemies that are normally animating seem to pause, hitch, or stop using the assigned animations when they are occluded, or off-screen. Is there a quality/performance setting I need to pay attention to in order to avoid this? How can I avoid this from happening?

On a similar note, let’s say 25 of these Ai characters animate perfectly, including their pony-tails. The pony-tails are attached to their heads, and bob and simulate perfectly with their movement animations. But if I add 25 more Ai characters, many of them start to exhibit static ponytails. They stop bobbing around. Could this be a similar issue related to performance?