It turned out to be a browser cache issue. First time I've ever had that as an issue. Maybe it's a thing with PG3x so I'll definitely look for that as a first step from now.
Hopefully this helps someone else.
Weatherflow support confirmed that one is not able to see other station data with API, even though the data is available via browser for all to see. Aside from asking them to make other station data available through API (limit it to a few, if needed) I also asked them to consider making the error message reflect what the error actually is, e.g. "NOT AUTHORIZED" or something like that, instead of "NOT FOUND".
