Here is the list of OpenStreetMap metro/subways validation results:
https://cdn.organicmaps.app/subway/ (hourly) or https://maps.mail.ru/osm/tools/subways/latest/ or https://alexey-zakharenkov.github.io/subways/rapid/
You can help us by fixing red metro lines directly in OpenStreetMap. Then every @OrganicMaps user will have an updated Public Transport map (subways and S-Bahn at the moment).
Some general instructions are here:
And here is info how to validate a separate city: