On certain buildings such as bushes or trees, that when you upgrade them, they have a 9 minute delay until they get upgraded. HOWEVER, when it goes past the 5 minute point, and you attempt to speed it up, it will show up with the same old, speedup items menu.
Not sure if intentional, and 5 minute speedup is only for buildings that have JUST 5 minutes or less on their original building time.
Thanks, XoGamer.