@Mendy - I think it really is a timing issue that can't be controlled by you at all. Murphy strikes hard there - if you try to time it to where you'll get sandbox immediately- NS will wait a day to do their part. If you try to time it with a delay - then it will get done earlier.

I actually did another refresh and this time it was good, NS support couldn't answer why that happened

@Mendy We've had this discussion with NS Platform team - Basically, they use a "recent" snapshot of the environment to raise the sandbox. The snapshots are usually taken between 12-1am local server time. So, Our companies best practice is to freeze any customizations/code promotions at least 48 hours before requesting a sandbox refresh. This allows time for NS to take a minimum of 2 snapshots. We then keep the freeze in effect and lock users out of the sandbox until the refresh has completed and is active.