looks like after the recent update the phone plugin widget container height does not fit the underlying custom plugin iframe content height. The phone plugin controls are now hidden and customers are unable to make calls using the phone plugin. So far, I was unable to alter the iframe container height from within the iframe. As far as I can see, the iframe container height could be only 'fixed' externally.
it was an issue on HubSpot side and resolved by HubSpot team. If the problem cannot be fixed on your side, requesting via your HubSpot' customers directly might speed up the process 🙂