sounds like a bug to me, please file a jira.

On Nov 14, 2014, at 3:21 AM, Vladimir Getmanshchuk <vladget@gmail.com> wrote:

For the scenario when used multiply dialstring:
 <action application="bridge" data="sofia/gateway/primary/dialstring|sofia/gateway/secondary/dialstring"/>

failure_causes which was sed to USER_BUSY,
only works when received 486 (USER BUSY) after 18x....
If it received 486 just after 100 Trying, it trying to bridge to the next gateway and ignore failure_causes=USER_BUSY...

Is it normal behavior?