we are facing weird behavior in SPO. We basically invite hundreds of users by using Azure B2B invitation. These users are added to a security group that is given visitor permissions to a SPO site. For most of the users the access works, but for some users it does not work at all. When you check user permissions, et shows that the user has been assigned Deny permission to almost everything. If you then explicitly add this user to a SharePoint group, after some time this Deny permission disappears and the user is able to use the site. The weirdest part is that this seems to happen totally randomly. Any idea what is happening? Do we need to add every user to the site explicitly?