I guess I'll count that as another reason to prefer managing it in situ. But it might be fine, actually? Slow re-accretion can probably be managed by whatever terraforming process we've kickstarted while most of it was gone.

Oh wait, I remember the plan, ship it to Mars so they can have some decent atmospheric pressure.

Mars could use only a small fraction of it. If the entire atmosphere of Venus were moved to Mars, the surface pressure there would be 120 bars (more at the lowest point).