I think this guy is not just a deserter, He’s an operative. He is now a muslim and is at war with the U.S. Along with Obamas help they helped get 5 major figures for the Taliban freed to re-enter a war against the U.S.
Bingo disco.
When Bergdahl deserted, and the entire group agrees that he did desert, (Not got drunk, etc.) his leader heard radio traffic (standing in the radio room) about him in some village asking if anyone could be an interpreter as he wanted to talk to the Taliban.
After he was gone, the attacks on the Americans became better. Instead of IEDs missing their marks, they were hitting the vehicles. Instead of random gunfire attacks on convoys, ambushes were much more planned and effective. This team leader conjectured that Bergdahl was filling them in on our tactics. Of course nothing that he could prove, but he, and others, immediately thought this upon seeing a pattern develop of more effective tactics by the enemy.