Hey @stevegb,
HubSpot looks at the UTMs (mostly campaign) and the channel source to set it’s original and latest values. You can read more here on how that’s done.
If you have a cookie banner, it could be that these sources are lost as a user hasn’t accepted or they’re simply declining to be tracked. Occasionally, the “First page seen” will contain these parameters and you could potentially setup workflows to revert the source back to what it should be. I’m also aware that Direct Traffic will sometimes be set in place of socials from Dark Social.