problem refresh ipv6 and release old ones ubuntu 14.04

[vigilian]

Hi,
I have a problem for several months now with ubuntu 14.04 but I d'ont verify with another distribution. Seems that my ipv6 stack doesn't release itself. (Don't know how to explain the situation). If I let my vm long enough up, if I run ifconfig I can see more and more ipv6 global which are very different and then I guess that's why i can't reach ipv6.google.com after a while. It's doesn't seem the case with windows 10 vm but I don't have as much as services activated on windows vm than my ubuntu vm.
any advice?
thanks
best regards

[vigilian]

it doesn't seems the case with debian 8.2, ubuntu 15.04 and windows. but all 14.04 ubuntu are affected by this. It keeps an old ipv6 + the new one but it seems to update the route table but i can't ping ipv6 website then after a renew of the adress
any idea?

[vigilian]

Is it possible that's caused by virtualbox? since I d'ont have any host on linux, i can't diagnose this like that.... How could I diagnose it?
Is it in the convention that the stack have to save the old ipv6 address? Isn't a system of to verify the sustainability of the old ipv6?