Guest users with Accepted invite status with No Groups or SP

We are working on cleaning up our list of guest users in our 365 tenant and I've come across about 150 guest users who have an Invitation State of "Accepted", but they are not a member of any group and they do not have access to any SharePoint sites.

My assumption is that at one point in the past they accepted an invitation to a group or SharePoint site, thus the reason their Invitation State is "Accepted", but since then that membership/access has been revoked. Can anyone confirm this?

OR can anyone lead me to a Powershell script that can give me the following info for guest users: Invitation State, Last login, 365 Group membership, SharePoint group membership?

Ultimately my question is how does a guest user have an Invitation State of Accepted, but then does not have access to anything?