You have missed the point.  This only happens when the client has an existing Intuit account!  For others that do not have an existing Intuit account there is no problem Link works well.  So here is what happens: You get a new client that used turbo tax or some other Intuit account 10 years ago, you invite them to link using their new contact data from your tax data file and Link finds that old account and contact data via Intuit and wants the client to use that old contact data to start using Link.  Again Intuit just does not care about the problem and has not fixed it!