This is not an unusual problem with suspended wooden floors.

The floor bounce is being transferred to whatever piece of furniture you have supporting your turntable.

Imagine holding a completely full glass of water while standing still - everything is fine unless you start to move, and then the water begins to splash around. That's what's going on with your turntable - your turntable is literally moving because its support is literally moving.

You need to either eliminate the floor bounce (good luck), or significantly increase the mass of whatever you have your turntable resting upon, so that it resists movement from floor bounce.

Wall-mounting is another effective solution, if that's a possibility for you.

Good luck!