I realize I'm late, and I hope you accept PS! battles as proof, because, according to links 1 and 2 with and without Marvel Scale respectively, Marvel Scale does activate and reduce damage.
I was bored and curios as well so I thought I'd test it out on PS!, but don't have proof aside from that if you're not okay with it :/
I can reason it out so (spoiler: it's obvious)
It attack first, and then cures paralysis, so Marvel Scale is in effect at the time damage is calculated.