There seems to be 2 locations created for Tallinn on meet.hn:
https://meet.hn/city/59.4372155,24.7453688/Tallinn (7 people)
https://meet.hn/city/59.4372420,24.7572693/Tallinn (1 person)
https://meet.hn/city/59.4372155,24.7453688/Tallinn (7 people)
https://meet.hn/city/59.4372420,24.7572693/Tallinn (1 person)
When I tried to register, I searched for 'Tallinn, Estonia' and there is only one location shows up from autocomplete.
However, the coordinates of that only Tallinn location is not the samame as previous 7 people.
So my guess is that at some point, ,the map/coordinate vendor's coordinates for Tallinn, Estonia have changed recently. And anyone trying to r egistetr for Tallinn will be registered with the new coordinates.