Is is a quite weird issue actually I provisioned with vRA 8.1 using NSX-T 126.96.36.199 (I know that is not the same version) and it worked smoothly more than 50 deployment so far.
Maybe this is not something with NSX or Horizon but with the template you are using. Check the next:
- Make sure you are using VMXNET3
- That you have the VMware Tools up-to-date
- Look for hidden network adapters in the Device Manager and uninstall them.
- Make sure that on your Windows the IPv4 you are using is show as preferred if you run ipconfig /all
Those are really quick tests to do and in my case they solved most of the issues.