Unavailable wifi showing up when connecting to any other wifi

Hello everyone,

I‘ve been having this weird bug since forever and have searched various times to find a solution.

Since I connected to a train‘s wifi (the OEBB WIFI) with my iPhone, it will pull up the default iOS login screen for that specific train wifi EVERY time I try to log into a wifi, even though there is no train or train station anywhere near me (for instance in other countries). Only Aater closing that window it will bring up the login screen for the wifi network I originally wanted to connect to. I have tried ignoring the OEBB network but it still shows up when I try to connect to another wifi.

Any guidance is much appreciated, thank you in advance!