Upgrading to Worpress 4.8 breaks web server

I have multiple wordpress sites managed under a single reseller. I just did the wordpress automated update on each of them, and they all stopped responding to http. Also, I could not log into user DA or ftp. Reseller could not change user password, said password invalid. I solved the problem by generating a new random password for each user. When I did that, http stared working, I could log in ftp, and log in user DA.

Wondering if anyone has any thoughts on this.