Hello, Looking for help or comments on this. Reproducible on the FS system that was updated about a month ago. Call scenario: SIP call comes in on "a" leg, SIP call is attempted on the "b" leg. "b" leg replies "404". Description of the problem: FS tries same SIP destination 4 times on the "b" leg instead of doing it once. It does not respond "404" to the "a" leg until it finishes all 4 attempts on the "b" leg. This occurs when "b" leg takes longer than usual to return "404". For example, if "b" leg takes 1.3 seconds until we get "404", FS tries the call on "b" leg 3 more times. When this happens each consequent call attempt on the "b" leg is exactly 2 seconds apart from when the previous call attempt ends. For comparison, in the same scenario and using exact same config, if "b' leg replies "404" sooner (e.g. within 0.3 seconds) FS does not retry this call on the "b" leg anymore. "404" is returned to the "a" leg instantaneously as it should be. I suspect this is a bug in Sofia such that is somehow related to 500ms timer. Is this known behavior? Do you need any more details to be able to verify or comment? Thank you, Victor