i'am using, for now, the free version of hubspot crm.
when i try to insert the form shortcode in a modal popup the form does not display correcty neither completly..
Could you share your account ID and a link to an example of the form? A screenshot of the behavior would also help.
HubSpot Marketing Hub Free and Starter forms are rendered in an
shell.js, which prevents custom scripts and styles on the page from affecting the form. This may be the cause for your issue.
Check out this related topic for more information on the difference between