Arrowverse Shows Renewed

That was arguably Joss' fault.  The show was doing well - I think it might have even seen an uptick in ratings, or at least was consistently strong - and there was no indication they wouldn't have been renewed at the usual time, it was just later than what Joss wanted, so he could plan ahead; so he pushed for an earlier answer and they said no.  
I'm not certain, but I kind of want to say the network may have even wanted to reconsider that decision later, but by that point it may have been too late.  I may be mistaken on that part, but the general consensus is that it was very much because Joss tried pressing for an early renewal; and the executive making the decision didn't want to make the commitment or backed into a corner.