I have 2 custom built basses (not EB) that are very, very similar in build materials. One has always needed a bit more attention in the truss rod dept than the other, which needs almost none at all. It’s the nature of natural materials, despite being the same wood, unless they’re from the very same plank of the same tree, they are likely to react differently to changes in climate. That being said, I think the older the instrument, the more stable they tend to be due to being an instrument that much longer, seasoning, whatever. I had a ‘63 P Bass that rock solid whenever, wherever, whatever the weather, I don’t remember adjusting it once in all the time I owned it.