It seems that Olsztyn city data is imported from GADM database https://gadm.org/maps/POL/warmian-masurian/olsztyncity.html.
The administrative boundaries are incorrect or map is simplifying the shape too much.
Please compare the map:
Wikipage is also not available:
Olsztyn city - https://pl.wikipedia.org/wiki/Olsztyn
Autogenerated link https://pl.wikipedia.org/wiki/Olsztyn%20City,%20WN,%20PL doesn’t exist.
Olsztyn County - https://pl.wikipedia.org/wiki/Powiat_olsztyński
Autogenerated link https://pl.wikipedia.org/wiki/Olsztyn,%20WN,%20PL doesn’t exist.
How these can be fixed?