So right now on PTR, If you use Resurrect during Valkyrie you have no speed penalty but you still have a cast time.
This may be a mistake but if its not it should be reverted. Right now its extremely easy to get out of range and cancel the rez without wanting to because the cast time is still there.
I dont know if this was an attempt to buff Mercy or a mistake since it wasnt in the patch notes but if they ant to buff mercy which I dont think they should do, the last place to put that buff is in Resurrect especially resurrect during valkyrie.