Golly I have one and have never had that issue. How old are your tarot nanos? Was there some sudden event prior to the nano doing that? A leak, a drop or anything? I'm thinking more information (from each of you) might help, although it does possibly sound like an electrical issue although the fact that it's the same issue for both of you makes me think there may be some sort of known "defect" or something although I've never heard of one.
Hopefully vapresso can help, if not maybe a vape shop would be of use in isolating the problem or at least telling you what it's NOT, etc. Because, if either is under warranty and it's an electrical fault you may not want to wait around. I realize not everyone has access to a "Great" Brick and Mortar with good mod diagnostic experts but it may be worth googling your locations to see if there is one. Etc:
Good luck,
Anna