IPSec bug with use of several SA´s

Hi folks,

following problem:
I have an IPSec Site-to-Site Connection from a RB1100 to a RB411

on the Clients which are the initiators there are 4 Policies with different Networks, the first one is the subnet to the RB1100 (here are dynamic SA´s configured)
All SAs are established, but i can´t ping the rb1100 in the specified subnet. All other devices in the three other subnets are immediately reachable

BUT when i disable and enable the first SA it is also possible to ping devices in this subnet

Does anyone know about this behaviour? what the hell can be the issue?