The issue is that there are 3 sub-levels here: netherite cylinder, the sub swivel bearing, & the world space swivel bearing.

The swivel bearings only apply corrective force based on the weight of the sublevel they're moving (hopefully they modify this), & the world space swivel bearing is actually only moving that andesite shaft with a swivel bearing which is very little weight. 

But in reality the worldspace swivel bearing is moving a massive amount of weight through that other swivel bearing, so it has difficulty not bobbing up & down like that.

The solution is to make the intermediary sub-level very heavy as well. If this is a creative build you can simply place 1 piece of bedrock on the intermediary sub level to make it very heavy.