Even though the extension link was sent out, something has gone terribly wrong with the 1 month grace time, so several of the markers have already disappeared from the map. As the setup is in the way that I would not keep the data, I can not recreate the points myself. I am trying to figure out what went wrong, because during testing phase the function seemed to work as intended.
I apologize for the inconvenience.
Who finds their link did not work and marker is missing, can simply add themselves again, just as the first time.