The AI tries to preserve the Titan and constantly uses the "retreat" function. Unfortunately that function atumatically chooses the closest jump point, making the thing jump back and forth. If you want to safe time and effort, place half your fleet at each entrance/exitpoint and bomb the frick out of the Ship that is behaving like so. You may even be luck and break it out of that beaviour, if the Ship doesn't consider you fleet a threat anymore.
Sometimes if your fleet is just a little stronger in fleet points spent the AI will also attempt to jump back in again after retreating just cause they got one or two frigates extra (tipping th balance "in their favor"). They won't even wait for their ships to heal, so you may end up with a 10% HP Titan coming back with a battered fleet just cause they now have few new LRMs.
tl;dr version: AI acts stupid. Ever has, probably always will.
I just hope they get the AI back to it's diplomacy skill-level where it at more or less acted like a "decent" first time player and not like a complete troll.
