This is very similar to the problem I had with 2008R2 (Win2k8R2 Obtaining DHCPv6 address, but has static configuration), but that solution doesn't work with 2012R2.
The box is a new 2012R2 domain controller, with a teamed interface to our LAN (where our desktop clients and other domain controller is). The other domain controller hands out DHCPv4 and DHCPv6. The 2012R2 controller only has the 1 interface:
netsh interface ipv6>show int
Idx Met MTU State Name
--- ---------- ---------- ------------ ---------------------------
1 50 4294967295 connected Loopback Pseudo-Interface 1
15 5 1500 connected LAN
Router Discovery, Managed Address Configuration and Other Stateful Configuration are all disabled on this interface:
netsh interface ipv6>show interface 15
Interface LAN Parameters
----------------------------------------------
IfLuid : ethernet_12
IfIndex : 15
State : connected
Metric : 5
Link MTU : 1500 bytes
Reachable Time : 38000 ms
Base Reachable Time : 30000 ms
Retransmission Interval : 1000 ms
DAD Transmits : 1
Site Prefix Length : 64
Site Id : 1
Forwarding : disabled
Advertising : disabled
Neighbor Discovery : enabled
Neighbor Unreachability Detection : enabled
Router Discovery : disabled
Managed Address Configuration : disabled
Other Stateful Configuration : disabled
Weak Host Sends : disabled
Weak Host Receives : disabled
Use Automatic Metric : enabled
Ignore Default Routes : disabled
Advertised Router Lifetime : 1800 seconds
Advertise Default Route : disabled
Current Hop Limit : 0
Force ARPND Wake up patterns : disabled
Directed MAC Wake up patterns : disabled
ECN capability : application
But the interface still obtains a DHCP address, even though it has been manually configured with a static address:
netsh interface ipv6>show address 15
Address 2001:44b8:4126:c615::22 Parameters
---------------------------------------------------------
Interface Luid : LAN
Scope Id : 0.0
Valid Lifetime : infinite
Preferred Lifetime : infinite
DAD State : Preferred
Address Type : Manual
Skip as Source : false
Address 2001:44b8:4126:c615:dc62:63e4:77e3:a0ad Parameters
---------------------------------------------------------
Interface Luid : LAN
Scope Id : 0.0
Valid Lifetime : 10d4h36m31s
Preferred Lifetime : 4d4h36m31s
DAD State : Preferred
Address Type : Dhcp
Skip as Source : false
Address fe80::d903:344a:627b:2289%15 Parameters
---------------------------------------------------------
Interface Luid : LAN
Scope Id : 0.15
Valid Lifetime : infinite
Preferred Lifetime : infinite
DAD State : Preferred
Address Type : Other
Skip as Source : false