Shared Links sent to guest users require #EXT#
Sending OneDrive links to a user that has existing guest access in MS Teams. Access seems to be granted to "EXAMPLE_domain.com#EXT#@OURTENANT.com" instead of "EXAMPLE@domain.com". User A enters their correct email address (which is entered accurately by User B who sent the link) and is greeted with "We couldn't find an account with that username." Users A & B have no way to know why error appears.