Updating contact email address back to previous one



Hi, I’ve seen an error a couple of times in our logs. When I update a user’s email address via the api to an email address they have previously used, I get a 409 error with the message, A contact with the email 'Optional[grant+apitest1@dissolve.com]' already exists. My steps to replicate this would be 1. Create a contact in hubspot. 2. Via the https://api.hubapi.com/contacts/v1/contact/vid/198301/profile api call, update the email address to a new one. 3. Use the same endpoint to update the email address to the original one.
Is this a bug or some conflict with the way hubspot uses email addresses as a primary key?