The use of Teams seems to be kind of half-implemented. When I create a Team and add it to a Share as I would a single user, the email notification does not send to the members of the Team even though it is included in the address list. Sending individually works fine.
Another issue with Teams is that the “count” of users shared with is not accurate. In the little panel on the right where it says “Shared with XXX internal users, XXX external users” the count doesn’t seem to reflect Team members, these are ignored.