We have just updated our Network License Tools (NLM) to 126.96.36.199. It can be downloaded here: www.autodesk.com/licensetools.
If you decide to upgrade, please follow this workflow:
Just a note that the 11.12 version of NLM was actually running in dual mode IPv4/IPv6 as noted in the log file so we rarely needed to swap out and use the IPv6 version of the Network Licensing Tools.
Log file from 11.12 NLM
Log file from 188.8.131.52 NLM
If necessary, be prepared for this workflow for swapping out IPv4 and IPv6 Network License tools: