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I am not the best to give advice here, but...
Going for the simple fix first maybe the bow hair is too tight. Also uneven bowing sometimes can cause a bounce. I was also told if my grip on my bow was too tight that could cause bouncing. And there is more about the bowing posture and how that can cause bouncing. (I am not really good with explaining good bowing posture). I hope some of the more knowledgable can chime in. Good luck with your bowing.
I never had a bow bounce in the beginning and now I seem to have it occasionally.
Vibrato Desperato.... Desperately seeking vibrato
I've found that one great exercise for forming that habit is to bow two strings at once. If you tune your violin by bowing two strings at once, you also get practice that will reduce bow bounce.