I don't roll cues to determine if they're straight. I showed you how I check each piece uing a flat surface and light, then if they're straight I can assemble them and turn them by sight to see if the joint is properly aligned.
I've dealt with Steven. He knows how to check a cue for straightness, so my assumption is the handle is indeed warped.
The problem is you have a cue made in one of the driest areas in the United States, Las Vegas, with 15% daytime humidity, and it lived in one of the most humid equatorial climates, Indonesia, with 80% humidity - where climate controlled homes are rare. In some parts of Indonesia, refrigerators are rare! By the way, about 30 years ago I beat all the players in Denpasar, so I am the Bali champion.
My guess is the cue is indeed warped and the seller is not adept at determining if the cue was straight.
Note in his original communications (Steven's first post) the seller acknowledges a wobble in the neck. That to me is the smoking gun. It's true that a parabolic taper accentuates any warp. he should have disclosed that the cue is not 100% straight as advertised.