I have seen this myself when an AD group was used to enable/disable accounts. If the user is not member of the designated group, the account will become disabled.
We are experiencing this exact same problem. I don't think any of the users are part of the AD group used to enable/disable accounts.
Would know of other possible causes?
Thank you in advance.
So that we can resolve this issue as soon as possible, could you reach out to the Enterprise Support team to investigate and fix this for you? You can access our Enterprise support number through your LastPass Admin Console > Support or request a callback by scrolling down and clicking "Contact Support" on this page and entering your Enterprise account info and you should then be given the option to receive a callback usually within less than 5 minutes: https://support.logmeininc.com/lastpass/help/how-do-i-contact-customer-support-for-lastpass-lp010121