Using invite_users() to invite external users to multiple groups not working

[DeirdreSmyth]

Hi There,

I have set up some code to be able to add a single user to multiple groups in arcgis online.  This works fine when using the add_users() method for an internal user but when I try to do it for an external user with the invite_users() method it returns the value 'True' but it doesn't actually do anything.  I have sent invitations to the same user using the button on the group page so the user and group are setup correctly.