Mentioning user in Google Chat space if they're a member of a Group for which you can't view members

[Neonsun]

Ran into an odd one today.

If you have a Google Group where the 'Who can see group' setting is set to 'Group members', and you add the group to a space, along with other users (or other groups), if someone tries to mention (@) a user in that space they will get a message asking if they want to add the user to the space (even if they are already a member through their group membership). Depending on whether or not the user is allowed to add members to the space, the mentioned user will be added to the space explicitly, outside the group, or the user that sent the message will get an error - and the mentioned user will have a strikethrough text formatting.

This likely happens because the user that mentions the other user isn't allowed to see if the user they're mentioning is a member of the group or not, but trying to add the user to the space probably shouldn't happen?