Lets explain the issue fully.
Arriving from reinforcements places the following restriction
p177 sidebar,
"Units that are set up in this manner cannot move or advance further during the turn they arrive - thier entire movement phase is used in deploying to the battlefield - but otherwise they can act normally (shoot, charge, etc.) for the res of the turn"
This places an explicit restriction on moving for the remainder of the turn.
Warptime states
"That unit can immediately move as if it were it's movement phase"
Now this does not explicitly counter the restriction applied from reinforcements, hence the argument that it still applies.
I believe it implicitly gives permission (as you are essentially getting a new movement phase, overriding the previous one) so movement would be allowed.