Case2 --One default router & Two network prefix--

At first

This is the case of "source address Dyna1 use can NOT pass default router of Power1". If Power1 choose Power2 as a default router, Dyna1 MUST choose 2001:200:0:8410:208:dff:fe76:f414 as the source address.
But Dyna1 choose source address at random.
So if Dyna1 can NOT connect at the probability of 1/2.

If Dyna1 choose 2001:200:0:8410:208:dff:fe76:f414 as the source address, Dyna1 can connect gr2000.

fig1)source address Dyna1 use can NOT pass default router of Power1

Interface rtk0 down

I exame if Dyna1 can connect gr2000, when Interface of Power1 down.

Result

Power1 change default router. But Dyna1 can change source address to 2001:200:0:8411:208:dff:fe76:f414.
So, data from Dyna1 is filtered by Power3.

This problem can not solve by existing implementation.
The structure which Dyna1 can know default router of Power1 is required.

fig2) Interface rtk0 down