I would say that this phrase has either been misheard or misunderstood in some way. Elizzy's guess is as good as any: "Bye for now" could sound like your sample phrase if said quickly and casually and is a very common phrase heard on parting.Hi, Dimcl and Elizzy,
the conversation is between a chinese student and a foreign professor. The student is raising this question on a forum, since he doesn't understand the saying. It could be that he misheard what the professor said. Many people responded they had never heard this before.