Well this was not about Imperial Intelligence having combat trained section (like special forces). I am sure it had this kind of section anyway. This was about drafting agents, spies and techs into front-line infantry. Most of them were trained in intelligence gathering and espionage and not in infantry combat nor had any combat experience.
It is not necessary for the game to specifically state whether it was a temporary or permanent assignment. The common sense tells you that sending (mostly) combat-inexperienced personnel into front-line infantry units means they didn't really value their actual expertise or expected to have any use them in the future. Lack of combat training and experience, front-line infantry assignment and heavy casualties in battle of Corellia would completely decimate the ex-intelligence personnel (and statistically it was a "death sentence" for majority).
Any agent regardless of their specialty will have had combat training, I get your point, but you are making it sound like they are sending out the lambs to slaughter which isn't the case. I'm a former US Marine and all Marines are rifleman first and foremost regardless of MOS, at anytime a Marine can be rotated into a combat element even if he was a cook,paralegal etc. They might not have as much experience as those of us with combat designations but they have the training and have seen guys like this excel and survive in combat.
The Sith probably did send the agents in hoping some would get slaughtered but knowing the Sith philosophy I think it was less about wiping them out and more about culling the weak from the strong for when the new Intelligence is rebuilt.