That is a little unusual, and I'm guessing there's a simple explaination why.
It is VERY common for them to surrender without a shot, or after overwhelming force shows up. In this instance, what I'm guessing happened is this: The insurgents were caught in a crossfire by U.S. and Iraqi reinforcements, as stated, and probably suffered casualties that have yet to be fully assessed or reported.
It's easy to report police/military casualties because we know everyone by name and number. It's harder with a large group of banged up insurgents. They were probably shipped off en mass to a holding area and whatever EKIA/EWIAs there were, are still being assessed, and as of the printing of the article, not yet reported. Given the poor level of detail in the article, I'm pretty sure that's what happened.
And it's worse than back to square one for them. That's a big net loss for that group, and we now have our hands on a large number of people that probably would rather talk to us than be handed over to the Kurds. Insurgents tend to give up quick, and spill the beans quick.
Oh they don't need to be turned over to the Kurds. There's plenty local and available to visit the terrorists scum.
And it's their worst nightmare. So let's have a Kurd officer in for a visit with the new prisoners.