Could have to do with the type of maple. My tech says that the more figured the wood the more susceptible to changes. Because in essence the figuring are knots in the wood and when they expand & contract wreak havoc.That is so contrary to most of the "knowledge " here. At least I'll admit to experience and not knowledge or book larnin'
I have other basses that have rock maple or quarter sawn maple and I never have issues with those. I have another bass that has a Wenge neck and I’ve never had to adjust it either.