I don't normally play against the Thalans so i don't know if this bug was in previous versions. But in my current game,
(YOR, IMMENSE, CHALLENGING), I have been at war with the Thalans for 3 years however I have not seen a single troop transport. SO i opened the trade window where i learnt to my suprise that they have yet to research Planetary invasion. They are currently the second most powerful race in the galaxy (i'm third). This seems rather a big bug, because if they are going to aggressively declare war on lots of races, WITHOUT planetary invasion, their just asking to get killied. I must assume this is a bug. Of course this could be becuase The Drath are forcing them into wars but even so you'd have though in 3 years they would have got round to researching this rather critical research and its NOT like i'm playing on CAKEWALK.