@krickster , I now see that you are correct, that despite the TSP generally being subject to 401(k) rules and being reported on a W-2 with the same code as 401(k) contributions, TSP contributions made while a NJ resident are not excluded from NJ income the way as 401(k) contributions.
See the reply by AmyC in this thread:
https://ttlc.intuit.com/community/state-taxes/discussion/new-jersey-tax-on-tsp-401-k-withdrawal/00/1...
