IPv6 stop working on clients after 72 hours

Hello! Can you help me please?
I have RB3011UiAS-RM, my ISP provides me /64 via DHCPv6-PD. I have a lot of devices and one Win10 “server” i never reboot. I added Google IPv6 and Google DNSv6 host to PRTG. Every 72 hours my IPv6 stop working until i reboot my server or reconnect patch-cord or off/on network card.
Other devices is working ok because it disconnects periodically (wifi phones, home pc etc).