Im a TEC player and i have the same problem. As soon as i get a a titan my fllet just goes brain dead. They will move together but they whont attack any nearby ships/fleet.
For an example my titan rushes in to a fight guns blazing while my HC's seems to know that they are in combat cous they activate there intercept ability but they are stuck on "reforming fleet" so they just fly right by the enemy.
Most of my fleet have the same attetude, they are set on "reform fleet" unless i manually tell them to attack a ship. When that ship is destroyed they go back to "reform fleet" and moves away to form up with the titan. I tried to let the ships do what they whant and se if they would attack after they had reformed the fleet but no they just sit there and take the dam.
I thought there was a setting somewhere ive missed but attack is on auto and the ROE is set on Gravity well. But it seems like its bugg and i hope they fix it soon cous i dont like plying as Advent or Vasari.