New York Times took a look at those soldiers claimed to have died "searching".
Bascially, there were eight deaths in the entire province shortly after Bergdahl left/desertted/whatever in a time period that was especially intense all over the country.
Two were defending an outpost, not out searching.
The other six deaths were months after the initial intense search was ended: one while looking for a Taliban leader, two doing recon, three during patrols in a historical "hotbed" of insurgents.
Yes, they were on the lookout for Bergdahl, but it's not like they wouldn't have been out there doing the same thing anyway. Kind of hard to make a cause and effect case.