It doesn't seem like you have too many ships in play, but targeting lists don't update instantly. This is the reason saturating the target lists by closing with the ships you want to "tank" all the damage works. They should switch after a short delay. In a fight of that size, I seem to get ~10 seconds of less optimal targeting. If it lasts much longer than that, something may certainly be wrong. I seem to recall that targeting is one of the most complicated systems in AIW.