Information:

Since the Anniversary Update (Build 1607) PCs with Windows 10 operating system no longer get an IPv6 address or extended configuration data via DHCPv6.

If you enter the command ipconfig /renew6 in the Windows command line, the client gets an IPv6 address, but after each PC restart, the client loses the IPv6 address again and does not get a new one.

Up to now (as of March 2017) Microsoft has not fixed this problem.