@ChristianBergerSipgate
Can you confrim that your $du contains a valid sip message? is it manually constructed or otherwise created? it seems to have a missing `:` in the `received` param.
`du=sip:1.2.4.129;lr;received=sip[2001:db8:0123:4567:89ab:cdef:dead:beef]:1234` should be `du=sip:1.2.4.129;lr;received=**sip:**[2001:db8:0123:4567:89ab:cdef:dead:beef]:1234`