I have an expensive Mark Bear ebony / birdseye fullsplice blank hanging in the shop that has moved ever since I got it. I have seasoned it, and worked it and actually sealed and finished it but it still moves. Summer time, like now, it's dead straight, but winter time it has a more than 1/8" wobble at the splice section. Unfortunately, it'll never leave as a complete cue. I will have to either cut it up to salvage the ebony, or try to do a full core when it's straight and hope it comes out ok. Wood does what it wants, when it wants to.
Dave
Not uncommon with full-splice cues.
Had a bocote-BEM cue that did the same thing.
Made it my house cue.
Cored short-splice are more stable imho.