I tried a simple case.
1. New scene.
2. Two sprites, one with a TweenColor on it that makes the sprite red. Another sprite has a UIPlayTween on it and a collider.
3. The UIPlayTween references the object with the TweenColor on it.
4. TweenColor is turned off -- both the tween is disabled in inspector, and the game object.
5. UIPlayTween is set to play OnClick, enable if disabled, and restart if finished.
6. Now I hit Play, click on the sprite with the UIPlayTween on it. The color of the second sprite changes smoothly, then the sprite gets disabled. I click again, the sprite gets re-enabled, and the tween works as expected. I click many times, the tween does not restart while it's running.
Everything works as expected. What are you doing differently?