Passwords App is hiding password it created for an App

I allowed the Passwords manager to create a new strong password for an App (the App is A Better Route Planner). It created this and put it into the Passwords App as I expected. However, when hovering over the password for the App, the series of dots (representing the password) is removed and there is a blank space, but no password shown (so can't be copied). Other passwords for other Apps work as expected. What have I done wrong, or how can I fix it?