^^This. Sounds stabilizer related. PBT warps easily, so the stabiliser and switch stem mounts may not line up nicely. If you remove the spacebar and lay it flat, is it bent or twisted at all? If so, you can pop it in some hot water for a while, then place it on a flat surface, put something softish on it to protect it and lay a bunch of books on top to keep it straight as it cools down.