Inactivating users

Inactivating users

I am an admin of my company, and we just recently started using Zoho CRM for our customer database. I've noticed many of my users will randomly become de-activated. I looked into it a little bit, and I noticed the users who are not currently logged in will become de-activated when I create a new user. Is this happening to anyone else, and is it intentional?

My Zoho CRM is integrated with Google apps premier, and I create users by inviting them through google apps. I don't know if this matters, but it's worth mentioning.