I've found a lot of very old reports about ghost links/fields, but all of them are from before 2020.
Today I cleared and then captured a portal that had links, and 3 of the links (and one field) stayed as ghosts (notice that the portal is blue and only has two resonators):
In the activity log there's no reference to these links. I think all the links the portal had were kept as ghosts.
These ghosts ARE preventing links crossing them, so it's not just a visual matter.
The portal is in -23.621165,-46.68402.