Aside: playing with the dates a bit may reveal the whereabouts of the possible owner, like: https://ttnmapper.org/devices/?device=hsnrgps2&enddate=2020-06-17 may indicate the device owner lives/works close to https://www.thethingsnetwork.org/gateway-data/gateway/eui-FCC23DFFFE0F5A7C
I’m quite sure I already contacted https://www.thethingsnetwork.org/u/hochschule_niederrhein about this, after this was mentioned in Slack August 15th, but I’m not 100% sure.
See also Who of you flew from Netherlands to Sweden? (TTN Mapper spammed)