don't know how "normal" it is, but the instant approval process definitely has some flags built in it. When it runs into one of those flags, the instant turns into a message of waiting. Many times, the outcome is good. I wouldn't fret until you hear.
Or you can be really obsessive and call and find out.
Jan 07: tu 498, ex 501, eq 504
Oct 07: tu 716, ex 712, eq 723
Nov 07: tu 693, ex 664, eq 672_post app frenzy