The term for white or cloudy marks is blush, caused by some type of moisture in the finish. Alcohol damage is more severe than water rings.
General Finishes tests all our topcoats against both isopropyl and denatured alcohol with results showing recovery within an hour.
In most cases, the white mark will fade if the spill is cleaned up in a timely manner. If the alcohol had been sitting on the surface for an extended period then it might not be able to bounce back.
HOW TO REMOVE WHITE MARKS
The afflicted surface needs to be scuffed and sanded first. Second, we recommend applying a sanding sealer to protect the top. Sanding sealer has a larger resin particle, so it will provide a better build for the next sanding step.
Learn more about General Finishes Enduro Sanding Sealer here.
Then finish with your topcoat.
Future forward, if you have a project that receives high-use, a glossier sheen will be more durable. The flatting agents that are required to formulate flat sheens cause a slight loss in durability and water resistance.
If you are set on a flat sheen on a new project, use two coats of semi-gloss first and finish with the flat sheen topcoat.