It sounds like at least some units has battery problems? Based on the description it sounds like water found its way into the battery compartment and short circuited something. A true product design nightmare.

That being said: I just don't understand the reason for the existence of this product. I'm a happy owner of an interdental water flosser and it is just not a problem aiming it at between my teeth. And the rare occasions when I mis-align and spray the water at my teeth is not an issue at all. And you feel when it is miss-aligned (or rather, not feel the water between your teeth) so it is not a thing I feel was in need of improvement.

I guess combining the water flosser with a toothbrush is nice, but does that need the whole camera stuff?