SSG140 | Huge udp packet losses

Good afternoon,

We are trying to solve out some strange issue with pair of SSG140 (6.3.0r23.0). We do see lot of UDP packet losses there, that can be 37% when traffic is around 1 (one) Mbps. So, for exampe, if we do test with 512Kbps -> almost no drops (1%), 1Mbps -> 37%.

One interesting thing: it's only for outbound traffic, not for inbund ... 

We tested that only on SSg140 (2 different pairs) - behaviour always the same. Any help?