Using a draytek 2820 with fw 3.3.5.2 with shrewsoft 2.1.7 client.
Using shrewsoft instaed of smart vpn because i need to use peer & remote id. This way i'm able to see which client is logged in AND i'm able to disable access from one client without the need to change the PSK for all client's

The problem that occurs is this. Client connect to draytek and when i try to ping the local network it takes 10 to 11 ping's before i get response. After the first initial local network contact no problem anymore. On every ping i get a avarage of 36mS response. Als RDP works without a glitch. Btw it does not mather if i use a virtual adapter (so i can tweak MTU) or a direct adapter.

When i make the first connection and forget about the ping and just try rightaway to make a RDP connection it takes twice before i get response. Als here, when i disconnect RDP and reconnect i get response right away.

This behavior is 100% reproducable!

So to resume. IPSEC connection no problem but the first, initial, contact with the local network has a delay. After that all works normal.
btw a PPTP connection does not have this behavior.

Any response in the right direction appreciated

sounds like either a firmware bug or feature of your vpn client- have u logged a support call with draytek?