Hiya,
Is this the post to which you are referring? https://stackoverflow.com/questions/58363278/how-to-block-multiple-sessions-on-single-account
I looked through our github issues and didn't see any open or closed issues about this functionality. So I think our current stance is, as the SO answer says:
There are many potential types of limits that could be put in place, such as limiting by IP, device, geographic location, session count, etc that these types of limits may be best solved by a Web Application Firewall (WAF) or some other specialized network security product.
However, we love to hear from users how to improve FusionAuth.
If this is an important issue to you, per our roadmap guidance, if you are a community member, please file a github issue. If you have an edition with support, please open a support ticket.