Simultaneous TCP connect on IPv6 stuck on NDP

[AwziNihilist]

If 2 routers try to connect to each other with TCP via IPv6 simultaneously, the communication gets stuck in a infinite loop of NS (Neighbor Solicitation) and NA (Neighbor Advertisement) packets.

So following topology:

results in following message exchange:

which loops for 47 simulation seconds + silence follows until the simulation ends.

If I delay one of the nodes by 0.1 seconds:

it works just fine. IPv4 works.

[ZoltanBojthe]

@AwziNihilist Please attach a minimal simulation (ini/ned files) for demonstrate this error.