When creating a connect to AD, what is the synchronnization period?

Both in the case of LDAP and Azure AD when the connections are created you choose the synchronization interval, and it includes:

• Relationships between users and groups. For example, consider User_1 who belongs to Group_1 in FME Server because of a corresponding relationship in the authentication service. If that relationship is subsequently broken in the authentication service, the relationship between User_1 and Group_1 will break in FME Server after the next synchronization interval. Likewise, if an authentication service user changes groups, that change will synchronize in FME Server.
• Name changes to user accounts on the directory server.