After we upgraded WordPress 2.9.2 to 3.3.1, along with individually turning back on plugins and updating, one of our admin accounts and all user accounts were locked out. Only the account that was logged in during the upgrade was allowed back in without resetting the password. The website owner is very concerned that this will happen again during future upgrades. Is there a stability issue with this that we should be aware of? Our membership site is growing and we cannot afford to have this problem again with a large membership base. Has anyone experienced this before?