I have a remote location that connects to the main office with two VPN tunnels. I found that priority (EF) traffic was being dropped on one tunnel, but not the other.
To resolve this issue, I am remarking all traffic to a DSCP value of Zero.
Here is the policy I used.
class-map match-all Remark-All-CM
set dscp default
interface FastEthernet0/0 (Inside Interface of WAN router)