Not sure if this is bad luck, or a bug.
If you practice on the training dummy in the brigand fortress until you get the message you can't practice any more today, then leave and come back, it will let you practice again, but you won't get any skillups.
If its actually locked for the day, I would have assumed to get the message again. If not, I would expect to get at least one skillup in two complete practice sessions.
Practicing is also a place where I've notice the skillup banners acting up. Sometimes they won't show at all while practicing, but if you check your stats you actually have gotten skillups.