Something that finally got cleared up at last is the deprecation of the IS-IS routing protocol from NSX. It has always been a bit of a confusing issue is it supported is it not ?
Well its been in the UI and the manual for a while however it was always my understanding that eventually this would be removed and from 6.2.3 this is now finally the case and should help clarify our position on using this protocol.
Deprecated and Discontinued Functionality
IS-IS is not a supported routing protocol for the Edge Services Gateway router
It will be removed from the UI and APIs in a future release. (Issue 1498251)