Zoom meeting link missing in email

We are connected to zoom via hubspot. and meetings are scheduled through HUbspot into Zoom. It has worked fine for years. But all of a sudden some of our meeting emails (the automatic ones sent once raised) are missing the zoom link. It seems to be sometimes the link is there and other times it is blank.

Screen shot showing where link should be.

Like i said sometime it happens sometimes it doesn't, so i have ruled out a setting issue