Financial or legal liabilities. Of the few rounds I got to see anything like transparency, I saw one get hung up because they had allowed an uncertified investor in during the seed. I think that guy might have been the only investor to get their money back because they had to buy him out and the money ran out before they closed the round.
(Some VCs are perfectly happy to let you run low on funds to get better terms).
(Some VCs are perfectly happy to let you run low on funds to get better terms).