The Optical Stabilization (OS, VR, IS, VC, etc.) feature found on many lenses and some camera models helps to reduce the camera shake in many of our images. However, it can also cause problems if left engaged when the camera is used on a tripod (see the samples below).
Take some photos on a tripod with the Optical Stabilization turned on and off and compare them to see if the negative effect is present when left on my accident. This can differ certainly between different brands of lenses and maybe even models. Also, if your lens has more than one OS Mode, pull up the instruction manual online and take the opportunity to learn exactly which mode should be used in what situation. Finally, make yourself a label that says, “Turn Off OS” and place it on the back of your tripod head to remind you so you don’t forget.