I’ve said it in ither comments on this thread I thought this was part of those.
Bad polling, handling of the border, how she ran the bay area when it came to marijuana charges and cases, perceived foreign policy goals especially in relation to Israel, bad public image towards young people (pokemon go to the polls energy) and a subpar debate record. From what I remeber she was solidly losing until the fly landed on Pence and he got memed to death.
In the end she will just be women trump or women biden, I.e more of the exact same.