highway=proposed is rendered
I realized that proposed highways are drawn in the equalstreetnames style, e.g. (https://www.openstreetmap.org/way/836131873#map=18/47.99088/7.85495) is visible (https://freiburg-im-breisgau.equalstreetnames.eu/en/index.html#18/47.99088/7.85495).
Im not sure if this is a deliberate choice, to show where progress is being made, but I find it rather confusing, especially since the name is not shown when clicking on the way.
Definitely not on purpose but I guess there was no highway=proposed in the other cities.
I'll update https://github.com/EqualStreetNames/equalstreetnames-template in the next few days to filter it out but you can already make the update for your city by updating the Overpass queries.