I did not read all comments so this could be a duplicate. Wood will always move. Even if I kilNed dried , planed it, etc to perfectly flat wood. Then sold it to someone in the next town. My shop might be a perfect humidity to keep wood from moving. It now goes to someone else's house or shop that has a slightly different humidity or it goes from summer to winter, the wood will collect or lose moisture unless used and sealed immediately. It will then warp. All wood will.some species less than others. look how people make solid wood doors. It's never one big pice of wood it's bits and pieces put together miteculously then sealed up right away. All 6 sides. Even when we buy 10,000$ solid wood door Systems. When it is delivered. It has a caveat that if not sealed all 6 sides within 4 weeks it will not be warranty. The first thing the door company does is remove the door to check top and bottom for proper urethane application. That way their door leaves the factory in winter or summer and is sealed within weeks. Some doors companies will only ship an expensive door that they have pre sealed it. Wood moves no matter what.
I've even bought perfect straight wood. Then ripped it down the middle. The stresses contained in the wood released and the two pieces bowed like s**t.
I've even bought perfect straight wood. Then ripped it down the middle. The stresses contained in the wood released and the two pieces bowed like s**t.