Not a surprise!

Because high-level generals were possibly involved, the Pentagon said, it raises questions about the loyalty and trustworthiness of Iraqi military officers at the highest levels.

Although he didn't mean it Bush has often said "when they stand up we will stand down". The Iraqi military and security forces are infiltrated by the very militias we are allegedly fighting. Considering the fact that the polling data would indicate a vast majority of the Iraqi population has become very anti American we should not be too surprised that the military reflects this. With that in mind this is not a surprise.
Two Senior Iraqi Generals Eyed in Brazen Attack on U.S. Soldiers

Two senior Iraqi generals are being questioned in connection with last week's attack in Karbala that left five U.S. soldiers dead, Pentagon officials told FOX News Thursday.

Military officials also said the level of sophistication of the attack — where militants posed as U.S. soldiers to pass a number of security checkpoints — suggested possible Iranian involvement.

The assault was carried out by nine to 12 militants wearing new U.S. military fatigues and traveling in black GMC Suburban vehicles — the type used by U.S. government convoys. U.S. officials said the imposters had American weapons and spoke English.

Also notice the reference to the Iranians. Much of the Iraqi Army is Shia and probably sympathetic with Iran. So what will the Iraqi Army do if Bush attacks Iran?