Anyone wash this with detergent and have it look like it’s drying again (i.e. white)?
No, but it hates ammonia.
Yes, it can reabsorb water, but it happened when sanding down decal set burn, cleared overnight
What kind/brand of detergent?
As GM noted, Future can be dissolved with ammonia. If the detergent you used has ammonia in it, it could certainly have attacked the Future coat. Even if it has other de-greasing agents, I’d be suspicious of trying it on a completed finish. There are other solvents that will dissolve Future, too.