HubSpot Support says, “The product team has confirmed that there is a limitation with HIPAA accounts. With these accounts, Zoom data can only be accessed directly through the Zoom platform and is restricted from being shared externally to comply with HIPAA regulations. As a result, we are unable to gather enough information for the integration to operate effectively.”
I found that those users currently in the HIPAA sub account do not have their Zoom accounts connect to HubSpot and have copied their meeting link from their settings on the Zoom website into the Location field on the meeting. This means they are sending out the same static meeting link for all meetings booked through the HubSpot meeting link. All that to say that HIPAA sub accounts will break the HubSpot Zoom Integration, but there is a way around it if needed.