just came to mind.
went to play and gun didnt air up correctly. realized that the reg didnt allow air to move. so i adjusted the reg back and forth. then it worked properly.
so bolt stick could be caused from reg if your pressure was not correct from the reg.
basically tech your reg. make sure its working properly. yeah it may chrono right when you chrono. but oring may be dry or etc.
that may help.
NT doesnt suffer from traditional "bolt stick". If you noticed the NT board doesnt even have an ABS setting. Something else is wrong with the gun and I doubt its as simple as lube.
I must have owned over 10 NTs and never had bolt stick but Ive had a slow returning bolt which is usually the front spool oring. Also change the #15 red oring and the bumper to the new orange one if you havent yet.